Cretaceous West Gondwana vicariance shaped … West Gondwana vicariance shaped giant water scavenger beetle biogeography ... subsequent biogeographical evolution is mainly driven by

ORIGINALARTICLE

Cretaceous West Gondwana vicarianceshaped giant water scavenger beetlebiogeographyEmmanuel F A Toussaint1dagger Devin Bloom2 and

Andrew E Z Short1

1Department of Ecology and Evolutionary

Biology and Division of Entomology

Biodiversity Institute University of Kansas

Lawrence KS 66045 USA 2Department of

Biological Sciences and Environmental amp

Sustainability Studies Program Western

Michigan University Kalamazoo MI 49008

USA

Correspondence Emmanuel F A Toussaint

Department of Ecology and Evolutionary

Biology and Division of Entomology

Biodiversity Institute University of Kansas

Lawrence KS 66045 USA

E-mail emmanueltouss1gmailcom

daggerPresent address Florida Museum of Natural

History University of Florida Gainesville

Florida 32611 USA

ABSTRACT

Aim We tested the hypothesis that ancient vicariance in giant water scavenger

beetles shaped their current distribution

Location Worldwide except Antarctica

Methods We inferred a molecular phylogenetic hypothesis for the tribe

Hydrophilini using probabilistic methods based on broad geographical and tax-

onomic sampling We used fossil-based molecular dating and likelihood

model-based ancestral range estimation to reconstruct the biogeography of this

clade

Results Our results suggest that the tribe originated in the Cretaceous about

120 Ma with a most likely ancestral range in the Gondwanan fragment com-

prising continental Africa and South America We infer an ancient vicariance

following this early origin consistent with the split of these two large land-

masses in the mid-Cretaceous The rest of the biogeographical history of the

group is shaped by dispersal events throughout the Cenozoic

Main conclusions The biogeographical history of hydrophiline water beetles

is consistent with the hypothesis of West Gondwana vicariance although an

origin in either Africa or South America is a likely alternative Although the

early cladogenesis of this clade might have been shaped by the opening of the

Atlantic Ocean subsequent biogeographical evolution is mainly driven by dis-

persal events

Keywords

Africa beetle evolution Cretaceous vicariance founder-event speciation

Hydrophilidae Hydrophilini South America West Gondwana biogeography

INTRODUCTION

The origin and biogeographical evolution of clades on Earth

is a paramount question in evolutionary biology (Lomolino

et al 2010) Several major mechanisms are commonly

invoked to explain the present-day distribution of biodiver-

sity including but not limited to dispersal vicariance and

regional extinction However it is not trivial to discriminate

among the roles played by these factors in shaping evolution-

ary histories Because of the development of increasingly

sophisticated methods to infer divergence times based on

molecular datasets and the fossil record (eg Drummond

et al 2012) and estimate ancestral ranges using model-

based approaches (reviewed in Ronquist amp Sanmartın 2011

Matzke 2013a) it is now possible to weigh the likelihood of

vicariance versus dispersal (andor regional extinction)

hypotheses in empirical studies It has been shown using

dated molecular phylogenies that disjunct distributions can

be accounted for by an ancient vicariance on the now sepa-

rated continental fragments of Gondwana Examples of such

patterns have been proposed for geckoes (Gamble et al

2008) stoneflies (McCulloch et al 2016) stag beetles (Kim

amp Farrell 2015) water beetles (Toussaint et al 2016 2017)

euedaphic ground beetles (Andujar et al 2016) and several

plant clades (eg Beaulieu et al 2013 Thomas et al 2014

Mennes et al 2015 Milner et al 2015 Berger et al 2016

Luebert et al 2017) Nevertheless a majority of clades

exhibiting potential Gondwanan vicariant patterns remain to

be explored using molecular dated approaches These might

be crucial to understand the relative contributions of

ordf 2017 John Wiley amp Sons Ltd httpwileyonlinelibrarycomjournaljbi 1doi101111jbi12977

Journal of Biogeography (J Biogeogr) (2017)

vicariance and dispersal in governing biodiversity assembly

through space and time in the Southern Hemisphere

The tribe Hydrophilini includes some of the most com-

mon and recognizable members of the water beetle family

Hydrophilidae Commonly referred to as the giant water

scavenger beetles the lineage includes some of the largest

aquatic beetles in the world with some exceeding five cen-

timetres in length Members are easily distinguished by a

sharply delimited lsquosternal keelrsquo that is formed by the fusion

and elongation of the meso- and metaventrites The mono-

phyly of the tribe has been strongly supported by cladistic

analyses based both on morphological (Short 2010) and

molecular (Short amp Fikacek 2013) data Taxa within the

Hydrophilini occupy a relatively narrow range of aquatic

habitats preferring open standing waters or the sluggish

margins and side pools of streams and rivers There are cur-

rently seven genera recognized within the tribe all of which

are easily diagnosed by suites of distinct morphological

synapomorphies (Short 2010) However the interrelation-

ships among these genera remain poorly understood

Giant water scavenger beetles are found in all the worldrsquos

biogeographical regions except Antarctica However this

diversity is not evenly distributed the majority of the grouprsquos

200 species are found in tropical regions and South America

alone is home to more than half of the known species (Short

amp Fikacek 2011) The tribe is one of the most fossil-rich

among the Hydrophilidae and its crown age was recently

estimated to be older than 120 million years ago (Ma)

(Bloom et al 2014 Toussaint et al 2016) Consequently

the diversification and biogeographical dynamics of this

lineage have been unfolding since before the breakup of

Gondwana

Using DNA sequence data from four loci and a broad tax-

onomic and geographic sampling we present the most

detailed phylogenetic and biogeographical analyses of the

tribe Hydrophilini to date to (1) infer the evolutionary rela-

tionships within the lineage (2) refine the age of the tribe

and its major clades and (3) reconstruct the biogeographical

history of the tribe to investigate the biogeographical origins

of hydrophiline diversity We specifically aim at testing the

contribution of vicariance versus dispersal in shaping the

biogeography of Hydrophilini

MATERIALS AND METHODS

Taxon sampling

In total 69 species out of approximately 200 described

(Short amp Fikacek 2011 unpublished data) from six of the

seven currently recognized genera were included (the sev-

enth the monotypic Protistolophus is only known from the

holotype collected in Venezuela) (see Appendix S1 in Sup-

porting Information for more details) Within the six genera

taxa were broadly sampled both taxonomically including 10

of the 12 included subgenera and geographically sampling

species from each genus across all biogeographical regions in

which they occur except for Australian representatives of

Hydrobiomorpha Most missing species belong to the genera

Hydrobiomorpha and Tropisternus and within these missing

taxa a large fraction is concentrated in South America Nev-

ertheless we have a good representation of Neotropical taxa

for these genera in our taxonomic sampling and therefore

are unlikely to lack major lineages Additionally missing

Neotropical species are supported as falling within already-

sampled Neotropical clades in Hydrobiomorpha both Old

and New World clades have unique synapomorphies of the

parameres of the male genitalia and have previously been

resolved as reciprocally monophyletic clades (Short 2010)

In Hydrophilus the missing Neotropical species are primarily

members of the subgenus Dibolocelus a lineage endemic to

South America except for one Nearctic species that we have

already included The well-defined genus Tropisternus does

not occur in the Old World and so any missing Neotropical

taxa would group with existing New World lineages There-

fore based on morphological evidence (Short 2010) we are

confident that most of the taxonomic and geographic diver-

sity of the tribe is represented in our sampling therefore

limiting possible biases in biogeographical analyses We

selected several outgroups including multiple representatives

of the sister tribe Hydrobiusini two more distant outgroups

from the tribes Amphiopini and Berosini and a representa-

tive of the closely related family Epimetopidae The selection

of outgroups was based on the most recent phylogenetic

studies of the family Hydrophilidae (Short amp Fikacek 2013

Toussaint et al 2016)

Molecular methods

From the dataset of Short amp Fikacek (2013) we used the

sequences of Hydrochara obtusata Sternolophus marginicollis

Tropisternus affinis T collaris and T lateralis as well as our

selection of outgroups All other Hydrophilini species used

in this study (64 in total) were sequenced de novo from

freshly collected tissues (see Table S1 for more information)

Specimens were preserved in 96 ethanol and kept frozen at

20 degC or below In a few cases pinned museum specimens

were used Total genomic DNA was extracted from legs with

a DNeasy kit (Qiagen Alameda CA USA)

Four gene fragments were amplified a 1764-bp fragment

of 18S rDNA a 696-bp fragment of arginine kinase (ARK) a

1025-bp fragment of 28S rDNA and a 750-bp fragment of

cytochrome oxidase 1 (CO1) Primers polymerase chain

reaction ingredients and thermocycler conditions were iden-

tical to those described in Short amp Fikacek (2013)

Trace files were edited and assembled in Geneious R

805 (Biomatters httpwwwgeneiouscom) All gene frag-

ments were aligned and refined using Muscle (Edgar

2004) as implemented in Geneious with default settings

Final alignments were adjusted by eye The final concate-

nated alignment consisted of 4235 sites Newly generated

sequences are deposited in GenBank under accession num-

bers KY554217-KY554442

Journal of Biogeographyordf 2017 John Wiley amp Sons Ltd

2

E F A Toussaint et al

Phylogenetic analyses

We inferred gene fragment tree topologies in a maximum

likelihood (ML) framework using Iq-Tree 15 (Nguyen

et al 2015) as implemented on the W-Iq-Tree web server

(httpiqtreecibivunivieacat Trifinopoulos et al 2016)

The different gene fragment alignments were left unparti-

tioned and the models of substitution were estimated using

the Auto function and selected using the Akaike information

criterion corrected (AICc) After confirming there was no

significant incongruence (Bootstrap value BS lt 70) among

gene fragment topologies (see Appendix S2) we combined

these into a concatenate matrix for analysis

We used Bayesian inference (BI) to reconstruct phyloge-

netic relationships in Hydrophilini using the concatenated

matrix The partitions and corresponding models of substitu-

tion were selected under PartitionFinder 111 (Lanfear

et al 2012) using the lsquogreedyrsquo algorithm the lsquomrbayesrsquo set of

models and the AICc Phylogenetic analyses were performed

using MrBayes 326 (Ronquist et al 2012) as implemented

on CIPRES (Miller et al 2010) Two simultaneous and inde-

pendent runs consisting of eight MCMC (one cold and seven

incrementally heated) running 30 million generations were

used with a tree sampling every 5000 generations to calcu-

late posterior probabilities (PP) We assessed convergence of

the runs by investigating the average standard deviation of

split frequencies and effective sample size (ESS) of all param-

eters in Tracer 15 (httpBEASTbioedacukTracer) A

value of ESS gt 200 was acknowledged as a good indicator of

convergence After discarding 25 of the trees as burn-in

the remaining trees in the posterior sample were pooled to

generate a 50 majority-rule consensus tree

W-Iq-Tree was also used to analyse this concatenated data-

set using 1000 ultrafast bootstrap replicates to assess nodal

support (Minh et al 2013) The dataset was partitioned using

the scheme of the BI analysis but the Auto function was used

to explore the fit of substitution models based on the AICc

Divergence time estimation

We inferred divergence time estimates using beast 182

(Drummond et al 2012) To avoid poor Markov chain

Monte Carlo (MCMC) chain mixing and convergence issues

the MrBayes topology was manually fixed by editing thexml

file generated in Beauti 182 Preliminary beast runs with-

out a fixed input topology resulted in trees highly similar to

the MrBayes majority-rule consensus tree although some

parameters consistently had low ESS values (data not

shown) The three distant outgroups Epimetopus Berosus and

Amphiops were pruned to avoid generating artefactual ages

because of a lack of constraint and moderate phylogenetic

resolution The molecular clock hypothesis was tested in

mega 6 (Tamura et al 2013) Since it was significantly

rejected (P-value lt 001) we used a Bayesian relaxed clock

approach We partitioned the data by gene fragments to infer

substitution rates for each of these and to facilitate

convergence of the runs The substitution and clock models

were unlinked in Beauti 182 (Drummond et al 2012)

The best-fit substitution model for each gene fragment was

searched in PartitionFinder 111 (Lanfear et al 2012)

using the lsquobeastrsquo set of models the lsquogreedyrsquo algorithm and the

AICc to compare the fit of the different models An uncorre-

lated lognormal relaxed clock was assigned to each gene frag-

ment partition and the Tree Model was set to a Yule or a

birth-death process The runs consisted of 50 million genera-

tions sampled every 5000 generations Convergence of the

runs was investigated using ESS a burn-in of 10 applied

after checking the log-likelihood curves and the different

runs merged using LogCombiner 182 (Drummond et al

2012) Comparison of fit between the Yule and birth-death

models was assessed based on the marginal likelihoods esti-

mated (MLE) using stepping-stone sampling in beast 182

(Drummond et al 2012) The marginal likelihoods were

estimated using a chain of one million generations and 100

steps with a = 03 We used Bayes factors to select the best

tree model using the 2log(BF) = 2x(logMLE1logMLE2)

index assuming a value gt 10 as strong evidence for a model

over another (Kass amp Raftery 1995) The MCC tree median

ages and their 95 highest posterior density (HPD) were

generated afterwards under TreeAnnotator 182 (Drum-

mond et al 2012)

We used four fossils to calibrate the phylogeny (1) Hydro-

biomorpha eopalpalisdagger from the Messel pit in Germany dated

from the mid-Eocene (Mertz amp Renne 2005 Fikacek et al

2010) was used to constrain the age of the genus Hydro-

biomorpha with an exponential prior distribution (Beauti

settings mean = 3875 offset = 4602) 95 of the distribu-

tion was constrained to encompass an interval comprised

between 47 and 189 Ma The latter age was selected based on

the median age estimate calculated for the subfamily

Hydrophilinae (Bloom et al 2014) (2) Hydrochara spdaggerfrom the same geological formation (Fikacek et al 2010)

was used to constrain the age of the genus Hydrochara

(Beauti settings mean = 3875 offset = 4602) (3) Hydro-

bius titandagger described from the Florissant Formation in Color-

ado (USA 339ndash372 Ma) This fossil belongs to the extant

genus Sperchopsis (Bloom et al 2014) and was used to con-

strain the age of this genus (Beauti settings mean = 4234

offset = 3283) (4) Baissalarva hydrobioidesdagger from the Baissa

deposits in the Buryat Republic (Fikacek et al 2014) was

used to constrain the age of the extant tribe Hydrobiusini

(Beauti settings mean = 1475 offset = 13460) As a result

of uncertainty in the intra-generic placement of these fossils

we used calibrations on stems rather than crowns

Ancestral range estimation

We inferred the biogeographical history of Hydrophilini

scavenger beetles across their entire range of distribution

with lsquoBioGeoBEARSrsquo (Matzke 2013a) as implemented in R

330 (R Core Team 2016) This program allows estimating

historical biogeography patterns under different models


3

Biogeography of Hydrophilini giant water scavenger beetles

combining vicariance and dispersal and implements a

parameter describing founder-event jump dispersal (j) This

free parameter allows a cladogenetic event where one daugh-

ter lineage inherits the ancestral range while another colo-

nizes a different one via founder-event speciation (Matzke

2013a) This parameter that has been shown in some biogeo-

graphical settings (eg archipelagos) to result in higher like-

lihood compared to models ignoring this parameter (Matzke

2013b) We conducted the analyses under the Dispersal

Extinction Cladogenesis (DEC Ree et al 2005 Ree amp Smith

2008) and DEC+j models using the beast maximum clade

credibility (MCC) tree with outgroups pruned (only Hydro-

philini representatives were kept) The following regions were

used in the analyses A Africa U Australian region (Aus-

tralia and Melanesia) N Nearctic S South America O Ori-

ental P Palaearctic We coded India as part of the Oriental

region although it was not part of this region until c 55 Ma

The distribution of each taxon was recovered from the litera-

ture (Hansen 1999 Short amp Fikacek 2011) andor from our

field notes To account for the extremely dynamic palaeogeo-

graphical events that occurred during the past 130 million

years (Myr) (Seton et al 2012) we designed four time slices

with differential dispersal rate scalers (s) between areas The

scalers were used to downweight the baseline dispersal rate

(d) between areas with respect to geographical barriers and

distance (Ree amp Sanmartın 2009) We followed the ensuing

rules dispersal between adjacent areas (dadj) is not penalized

(dadj = 10d) dispersal between areas separated by a small

water barrier (dswb) is downweighted by a scaler value of

075 (dswb = 075d) dispersal between areas separated by

another area (dar) is downweighted by a scaler value of 050

(dar = 050d) and dispersal between areas separated by a

large water barrier (dlwb) is downweighted by a scaler value

of 025 (dlwb = 025d) The dispersal rate matrices for the

four time slices between all possible area combinations were

calculated following these rules and considering multiple bar-

riers and landmass discontinuities throughout the timeframe

of the grouprsquos evolution (Seton et al 2012) We selected the

shortest path between two areas to impose the dispersal rate

scalers [eg dispersal between Africa (A) and the Australian

region (U) in the first time slice (130ndash80 Ma) was scaled by

025 because at that time those two regions were separated

by Antarctica (s = 050) but also by a small water barrier

(s = 025)] In the case of areas separated by several barriers

andor landmass discontinuities we chose in a conservative

manner to use a minimum scaler of s = 005 to take into

consideration unlikely long-dispersal events Finally we

allowed different adjacency matrices in the four time slices

(Fig 1) The rationale was to allow different ancestral ranges

(0 or more areas) in each time slice to take into account the

palaeogeographical rearrangements of landmasses throughout

the Cenozoic As a result a unique continuous-time Markov

Chain (CTMC) was used for each time slice For each time

slice the downpass likelihood of non-existing ranges was set

to 0 and non-existing ranges were removed from the rate

matrix (Matzke pers comm)

RESULTS


The partitioning scheme and substitution models selected in

PartitionFinder are given in Table 1 All partitions

included in the MrBayes analyses had a GTR+I+Γ model

The results of our phylogenetic analyses are summarized in

Fig 2 We recover Hydrophilini monophyletic with strong

support with Hydrobiusini as its sister taxon (PP = 099

BS = 89) The tribe is divided into two primary clades C2

(PP = 095BS = 89) and C3 (PP = 091BS = 77) respec-

tively comprising Hydrobiomorpha + Hydrophilus and

HydrocharaBrownephilus + (Sternolophus + Tropisternus)

Most hydrophiline genera including Hydrobiomorpha

(clade C4 PP = 1BS = 100) Hydrophilus (clade C5 PP = 1

BS = 100) Sternolophus (clade C7 PP = 1BS = 100) and

Tropisternus (clade C8 PP = 1BS = 100) are all resolved as

monophyletic with strong support The middle-eastern ende-

mic genus Brownephilus is found deeply nested within

Hydrochara which otherwise is strongly supported as mono-

phyletic (clade C6 PP = 1BS = 100)

Divergence time estimates and ancestral range

estimation


PartitionFinder are given in Table 2 The beast analyses

converged as indicated by the stationarity of the MCMC and

ESS values above 200 Based on Bayes Factor comparisons

the birth-death model (Ln = 3059321) was preferred over

the Yule model (Ln = 3059321) though both models gave

very similar dating estimates (Table 3) The estimated rates

of gene fragments were also highly similar between the two

models (Table 4) The median ages across the phylogeny of

Hydrophilini based on the birth-death model are presented

in Fig 3 along with the 95 credibility intervals of the most

important nodes lsquoBioGeoBEARSrsquo favoured the DEC+j model

over the DEC model with a significant difference in log-like-

lihood (LnLDEC+j = 9719 against LnLDEC = 12233)

Results from both analyses (the ancestral ranges receiving the

highest relative probability) are mapped on the phylogeny in

Fig 3 (see Appendix S3 for more details on alternative

ranges and uncertainty in reconstructions)

Under the estimated DEC+j model (e = 00000 d = 00028

j = 00841) we infer an origin of the group in the joint area

Africa+South America (AS West Gondwana) about 120 Ma

during the Lower Cretaceous (Fig 3) We infer a subsequent

vicariant event leading to a clade in Africa comprising Hydro-

biomorpha and Hydrophilus and another in South America

comprising the rest of the tribe In Hydrobiomorpha Africa is

colonized via dispersal from South America in the Palaeocene

Eocene In Hydrophilus the Oriental region is colonized from

South America in the Upper Cretaceous The Australian

Nearctic and Palaearctic regions are colonized from South

America respectively between the Upper Cretaceous and


4


mid-Eocene and in the Eocene We infer an EoceneMiocene

colonization of the Palaearctic region out of Africa in Hydro-

chara with subsequent colonization of the Nearctic region in

the Miocene We infer two Miocene dispersal events out of

Africa in Sternolophus toward the Australian and Oriental

regions In Tropisternus we infer a range expansion in the

Figure 1 Dispersal rate scaling matrices used in the lsquoBioGeoBEARSrsquo analyses Summary of the time slices used in the lsquoBioGeoBEARSrsquo

analyses and arranged from top to bottom in inversed chronological order Each time slice (TS1 to TS4) is presented with a mapderived from Seton et al (2012 copyright permission from Elsevier with order number 4007750560480) and a matrix of dispersal rate

scalers relative to potential geographical barriers and distance Several symbols are used to represent the possible barriers between thechosen areas A Africa U Australian region O Oriental region S South America N Nearctic P Palaearctic


5


Eocene toward the Nearctic region and a dispersal event out of

South America toward the Nearctic region in the Oligocene

The rest of present-day distribution of Hydrophilini is the

result of late dispersal events

Although most of the biogeographical pattern inferred is

robust with high ancestral range probabilities across the

chronogram some important nodes have equiprobable esti-

mated ancestral ranges (Fig 3) This is the case for instance

of the nodes corresponding to the root and clades C2 C4 C5

and C6 for which the second most likely ancestral range

received a relatively high likelihood (Fig 3 see Appendix S3)

Under the estimated DEC model (extinction rate = 001

dispersal rate = 001) the ancestral range with the highest

probability still supports a vicariant initial pattern in West

Gondwana although with lower probability Clade C2 is also

inferred as ancestrally Neotropical with subsequent range

expansion toward Africa in Clade C5 in the Upper Cretaceous

This scenario would imply local extinction in Africa followed

by recolonization of this region when both landmasses had

already been drifting apart for 20ndash30 Myr therefore invoking

long-distance dispersal The biogeographical scenario in Clade

C3 is different from the one inferred under the DEC+j model

Africa is the ancestral range but the daughter nodes present a

vicariant pattern respectively in Africa+Palaeacritc and Afri-

ca+South America In Clade C6 the ancestor would have

shifted its range toward the Nearctic region in the Oligocene

which is in line with palaeogeographic configuration at that

time The rest of the biogeographical history in C6 would

imply several vicariant events between Nearctic and Palaearctic

in the Oligocene and Miocene In clade C7 the most notable

change in comparison to the DEC+j model is the transition

from Africa to a wide range in Africa+Oriental region before a

dispersal event toward Australia in the Oligocene-Miocene In

clade C8 the DEC model recovers vicariant events instead of

dispersal events to explain the distribution of Nearctic Tropis-

ternus species

DISCUSSION

Systematics of Hydrophilini

Our recovered topology (Fig 2) largely agrees with prior

hypotheses of Hydrophilini relationships based on adult

morphology (Short 2010) with two notable exceptions the

monophyly of Hydrochara and the placement of the root

Short (2010) had resolved Hydrochara as a weakly supported

paraphyletic grade while we resolve the genus as mono-

phyletic with strong support and with the inclusion of Brow-

nephilus which contains two enigmatic species from the

Middle East This is not a surprising outcome as Hydrochara

has always been considered a natural group and shares

aedeagal morphology with Brownephilus Additional exami-

nation of the morphology of these two genera and a formal

synonymy of Brownephilus with Hydrochara is forthcoming

(A E Z Short unpublished data)

Though the unrooted networks are congruent the place-

ment of the root differs from Short (2010) After accounting

for the absence of Protistolophus in our analysis the compara-

ble root would insert between the Sternolophus and

the reminder of the Hydrophilini while we inferred it along

the branch between (Hydrobiomorpha+Hydrophilus) and

[Hydrochara+(Sternolophus+Tropisternus)] We believe our

inferred root placement is more congruent with the observed

morphological diversity and distributions of the genera Addi-

tionally even if the other root placement had been recovered

it would not alter a West Gondwana origin of the Hydrophilini

as Protistolophus is a Neotropical endemic and the ancestral

rage of Sternolophus is resolved as Afrotropical in our analysis

Biogeography of giant scavenger water beetles

Our results suggest with moderate support an ancestral origin

of the Hydrophilini in a vast region encompassing both Africa

and South America (ie West Gondwana) in the Lower Creta-

ceous about 120 Ma (Fig 3) At that time these regions were

largely connected and only began to drift apart in the mid-

Cretaceous from 120 to 100 Ma (Seton et al 2012) Follow-

ing this initial vicariance the biogeographical evolution of the

group was mainly driven by dispersal (but see the DEC model

in Fig 3) The dispersal events inferred in clades C4 and C5

respectively from South America toward Africa or Australasia

require a trans-oceanic dispersal explanation or continental

dispersal through Antarctica followed by extinction in the lat-

ter case Trans-oceanic dispersal events have been suggested

on other water beetle clades for instance in Platynectini div-

ing beetles (Coleoptera Dytiscidae) from the Oriental region

Table 1 Partitioning scheme and substitution models for the

W-Iq-Tree analyses

Partition name Composition W-IQ-TREE AICc model

P1 CO1 pos2 TIM2+I+GP2 CO1 pos1 TPM3+IP3 CO1 pos3 TIM2+I+GP4 ARK pos1 TPM3u+I+GP5 ARK pos2 K3P+I+GP6 ARK pos3 TPM2+I+GP7 18S TNe+I+GP8 28S GTR+I+G

Figure 2 Molecular phylogeny of the tribe Hydrophilini The topology derived from the MrBayes analysis is presented with nodal

support of the BI and ML analyses as indicated in the inserted caption The black vertical bar delimits outgroups used in this study andthe grey ones delimit the different genera of the tribe Hydrophilini Hydrochara and Brownephilus being found in a single clade the

paraphyly of the former is highlighted with a dashed vertical bar On the left part of the figure is presented a habitus of Hydrophilus

rufomarginatus from Africa


6



7


toward South America (Toussaint et al 2017) In clade C5

the dispersal from South America toward the Oriental region

(Fig 3) has to be explained by long-distance dispersal in the

Upper Cretaceous possibly toward India that at this time was

part of East Gondwana (Gibbons et al 2013) The lineages

would have persisted on the Indian plate until its docking

with Eurasia 30 Myr later (Seton et al 2012) Despite the

intense volcanism recorded during the drifting of India

examples of clades that survived such dramatic conditions

have been suggested (eg Toussaint et al 2016) The African

continent was later recolonized via range expansion in the

genus Hydrophilus (Fig 3) The colonization of the Palaearctic

region out of South America in C5 is puzzling and could

either result from a long-distance dispersal event or from dis-

persal via the Nearctic region followed by regional extinction

In clade C6 the Palaearctic region was colonized from Africa

when both landmasses were very close (Fig 1) The genus

Sternolophus also presents some intriguing biogeographical

patterns such as a dispersal event from Africa toward Aus-

tralasia in the OligoceneMiocene possibly using the Kergue-

len plateau as a stepping-stone as hypothesized in allodapine

bees (Hymenoptera Apidae) (Schwarz et al 2006)

Our results moderately support the West Gondwanan

vicariant scenario (relative probability P = 18) with two

slightly less likely origins Afrotropical (P = 15) or wide-

spread (Africa+South America+Oriental P = 15) Consid-

ering the incomplete sampling in Hydrophilus and the

equiprobable Afrotropical origin (P = 29 Fig 3) of the

clade supported as being Oriental (P = 30) in the DEC+janalyses we believe that the widespread origin scenario is

less plausible than the two other alternatives (West Gond-

wana and Africa) In the Afrotropical origin scenario the

tribe would have dispersed across the Atlantic Ocean toward

South America This scenario is less straightforward than the

West Gondwana vicariant one but does not seem completely

implausible considering that such dispersal occurred at least

another time with the ancestor of Tropisternus (Fig 3)

Though the DEC model received significantly less support

than the DEC+J model in lsquoBioGeoBEARSrsquo it is relevant to


beast analyses

Partition name PF AICc model

ARK GTR+I+GCO1 GTR+I+G18S TrN+I+G28S GTR+I+G

PF PartitionFinder AICc Akaike information criterion corrected

Table 3 Median divergence time estimates of major nodes

within Hydrophilini as recovered in the beast analyses

Node

Yule model

(95 HPD)

Birth-death model

(95 HPD)

Root 13845 (13460ndash15083) 13846 (13460ndash15125)Hydrobiusini 8493 (6518ndash10765) 8552 (6508ndash10891)C1 (Hydrophilini) 12385 (10308ndash14349) 12253 (10067ndash14149)C2 11781 (9670ndash13649) 11630 (9600ndash13629)C3 11471 (9377ndash13529) 11396 (9183ndash13350)C4 (Hydrobiomorpha) 6598 (4721ndash8474) 6547 (4758ndash8526)C5 (Hydrophilus) 9512 (7676ndash11305) 9397 (7604ndash11247)C6 (Hydrochara) 4264 (2980ndash5793) 4256 (2973ndash5809)C7 (Sternolophus) 3770 (2712ndash5006) 3728 (2710ndash4989)C8 (Tropisternus) 5778 (4348ndash7329) 5717 (4348ndash7300)

Median ages in millions of years (Myr) HPD highest posterior

density

Table 4 Rates of the different gene fragments in Hydrophilini as estimated from the beast analyses using Bayesian lognormal relaxedclocks

Gene

Yule model Birth-death model

Mean rate ( SD) ucldmean ( SD) Mean rate ( SD) ucldmean ( SD)

CO1 001041 000136 001123 000172 001045 000134 001135 000174

ARK 000060 000007 000061 000008 000060 000007 000061 000008

18S 000006 000001 000007 000001 000006 000001 000007 000001

28S 000052 000006 000060 000011 000052 000006 000060 000010

Mean rate number of substitutions per site divided by the tree length ucldmean mean of branch rates SD standard deviation

Figure 3 Divergence times and palaeobiogeography of the tribe Hydrophilini Chronogram derived from the MCC tree beast analysis

presenting the median ages estimated as well as the 95 credibility intervals (horizontal grey bars) Range distribution of each species isgiven on the right of the chronogram following the colour-coded caption inserted at the bottom of the figure The most likely ancestral

range as estimated under the DEC+j model in lsquoBioGeoBEARSrsquo is presented at each node as a coloured square Nodes for which the

likelihood of the ancestral state is superior to 50 are highlighted with an asterisk For major nodes with lower probability the threemost likely states are presented in a box For more derived nodes with low probability only the second most likely state is given with a

letter corresponding to the inserted caption The results of the DEC model are also presented with coloured circles for each node wherethe ancestral estimated range differs from the one estimated under the DEC+j model For more details on the relative probabilities of

both models refer to Appendix S3 The timeframe of West Gondwana (Africa and South America) breakup is indicated by a large greyrectangle and a representation of the two landmasses c 100 Ma according to the model of Seton et al (2012)


8



9


compare results from the two methods here The founder-

event jump dispersal parameter j has been proven to be par-

ticularly relevant in island systems (Matzke 2014) where it

often significantly improves the likelihood of the model

However it is not entirely clear if or how this parameter is

relevant in continental island-like settings and more impor-

tantly in non-island-like continental settings In Hydrophi-

lini the j parameter is the main factor explaining the

biogeographical history of the group whereas the role of

extinction and range expansion is much reduced (see

Results) Considering the inferred negligible value of the

extinction parameter e in DEC+j it seems difficult to invoke

range expansion followed by extinction in hydrophilines In

contrast in the DEC model extinction and range expansion

play a crucial role as illustrated by the complex biogeo-

graphical scenario inferred (Fig 3 see Appendix S3) Indeed

most range expansion and vicariant events inferred by the

DEC model are difficult to reconciliate with the arrangement

of landmasses at the time without invoking regional

extinction

The fossil record indicates that at least some regional extinc-

tion has occurred in Hydrophilini (Fikacek et al 2010) Four

genera of Hydrophilini have Eocene representatives that have

been found in the Palaearctic region and two have Eocene rep-

resentatives from the Nearctic region Although our biogeo-

graphical reconstructions are consistent with such

distributions in Hydrochara (Palaearctic) Hydrophilus (Nearc-

tic and Palaearctic) and Tropisternus (Nearctic) the lack of

present-day Palaearctic Hydrobiomorpha suggests regional

extinction Thus although the DEC+j model receives a much

better likelihood than the DEC model it might not entirely

capture the complexity of the evolutionary history in this

group The DEC model on the other hand recovers extinction

and range expansion as important forces driving the biogeo-

graphical evolution of hydrophiline water beetles It also

implies biologically intricate biogeographical processes such as

repeated long-distance dispersal and regional extinction which

might be obscured by a potential role of Antarctica in shaping

the biogeography of the group Despite the stronger statistical

support for the DEC+j model over the DEC model it is not

clear which model is the most appropriate in the case of

Hydrophilini biogeographical history Unfortunately it is not

presently possible to place the described fossils in the present

phylogenetic framework because there is not enough morpho-

logical support for the inclusion of these taxa beyond generic

assignments Therefore it will be important to revise the

inferred patterns in the light of denser taxon sampling and bet-

ter knowledge of the fossil record as these can partly obscure

macroevolutionary patterns (eg Meseguer et al 2015 Tous-

saint amp Condamine 2016)

Comparison with other West Gondwana vicariance

patterns

Our ancestral range estimation recovers with moderate sup-

port a West Gondwana vicariant pattern with a joint ancestral

distribution in these two regions A recent study on Sericini

chafers (Coleoptera Scarabaeidae) recovered a similar pattern

with the best biogeographical model estimating a vicariant

split consistent with the West Gondwana vicariance hypothe-

sis (WGVH) (Eberle et al 2017 Fig 4) Likewise Luebert

et al (2017) recovered a potential case of vicariance support-

ing the WGVH in Boraginales (Asterids) with the upper

bound of their age estimate slightly overlapping with the tim-

ing of West Gondwana break-up (Fig 4) Flowering plants of

the families Combretaceae (Rosids Myrtales) and Elatinaceae

CentroplacaceaeMalpighiaceae (Rosids Malpighiales) have

also been recently suggested as a potential example of West

Gondwana vicariance (Berger et al 2016 Cai et al 2016)

Some clades with exclusive sister relationships between

Afrotropical and Neotropical lineages have been suggested as

good candidates for the WGVH For example the divergence

of the freshwater fish sister genera Arapaima and Heterosis

(Teleostei Osteoglossiformes) respectively found in South

America and Africa was dated from the Cretaceous (Fig 4)

Although the dating analyses were somewhat contradictory

these osteoglossiform fishes are amongst the best candidates

for the WGVH (Lavoue 2016) Aciliine diving beetles

(Coleoptera Dytiscidae) have also been suggested as a candi-

date for WGVH (Fig 4) although the results of dating anal-

yses were inconsistent when based on either crown or stem

fossil placement (Bukontaite et al 2014) A more compelling

example is found in the gecko family Sphaerodactylidae in

which Gamble et al (2008) recovered as split between Mor-

occo and Neotropical geckoes in the Upper Cretaceous con-

sistent with the WGVH In caecilians the family

Dermophiidae endemic to South America has been resolved

as sister to Siphonopidae distributed on each side of the

Atlantic Ocean with Neotropical siphonopids being the most

derived clade in the family The dating of the split between

the two families has been somewhat controversial with esti-

mates largely spanning the Lower Cretaceous (Kamei et al

2012) and younger ones postdating the West Gondwana

break-up (Pyron 2014)

In contrast other studies focusing on clades with a well-

supported sister-group relationship between Africa and South

America have rejected the WGVH For instance Givnish

et al (2004) suggested a very recent Miocene divergence

between the AfricanSouth American disjunct lineages in

Bromeliaceae and Rapateaceae suggesting long-distance dis-

persal Likewise the divergence between the African wild

almond genus Brabejum and its sister genus Panopsis from

South America was dated from the Eocene (Barker et al

2007) therefore rejecting the hypothesis of a West Gond-

wanan signature Other examples of molecular divergence

time estimates that are irreconcilable with the WGVH are

also found in cichlid fishes (Matschiner et al 2017 but see

Lopez-Fernandez et al 2013) amphisbaenian worm lizards

(Longrich et al 2015) Leguminosae (Meng et al 2014)

and Sapotaceae (Bartish et al 2011)

Although we relied on a rather limited fraction of the total

diversity of hydrophiline water beetles we included most of


10


Figure 4 Examples of clades supporting the West Gondwana vicariance hypothesis Overview of clades for which the West Gondwanavicariance hypothesis (WGVH) was suggested based on molecular dating andor model-based biogeographical estimationreconstruction

The divergence times for the focal nodes representing the split between Africa and South America are given for each clade as credibilityintervals Names with an asterisk indicate that in the selected study an alternative analysis did not support the WGVH For more details

on these alternative analyses please refer to the original publications The timeframe of West Gondwana (Africa and South America)breakup is indicated by a large grey rectangle and a representation of the two landmasses c 100 Ma according to the model of Seton

et al (2012)


11


the taxonomic and geographical diversity for each genus

Given that the missing taxa can be morphologically assigned

to sampled clades and more specifically that missing

Neotropical taxa are morphologically supported as members

of sampled Neotropical clades the possibility that our bio-

geographical estimation is biased by incomplete taxon sam-

pling is very unlikely The lack of an exclusive sister

relationship and the moderate relative probability for a sce-

nario supporting the WGVH suggest that a conservative view

of hydrophiline biogeographical history is prudent Future

empirical studies with denser taxon sampling will help to

confirm or revise this evolutionary pattern This study adds

to the scarce literature supporting the WGVH and is thus

important to our understanding of the relationship between

Gondwanan tectonic events and biogeographical evolution of

clades in the Cretaceous There is no doubt that the increas-

ing number of empirical studies using molecular dating and

model-based approaches will shed new light on the heated

debate between ancient vicariance and dispersalism

ACKNOWLEDGEMENTS

We would like to acknowledge the editors Mike Dawson and

Isabel Sanmartın as well as three anonymous reviewers for

constructive comments on earlier drafts of this paper We

thank the many colleagues that contributed tissues for this

study Kelly Miller Ignacio Ribera Michael Balke Robert

Sites Yusuke Minoshima Johannes Bergsten and Michael

Caterino Martin Fikacek provided material as well as critical

analysis of the fossil calibrations This study was funded in

part by a University of Kansas General Research Fund grant

to AEZS

REFERENCES

Andujar C Faille A Perez-Gonzalez S Zaballos JP

Vogler AP amp Ribera I (2016) Gondwanian relicts and

oceanic dispersal in a cosmopolitan radiation of euedaphic

ground beetles Molecular Phylogenetics and Evolution 99

235ndash246Barker NP Weston PH Rutschmann F amp Sauquet H

(2007) Molecular dating of the lsquoGondwananrsquo plant family

Proteaceae is only partially congruent with the timing of

the break-up of Gondwana Journal of Biogeography 34

2012ndash2027Bartish IV Antonelli A Richardson JE amp Swenson U

(2011) Vicariance or long-distance dispersal historical bio-

geography of the pantropical subfamily Chrysophylloideae

(Sapotaceae) Journal of Biogeography 38 177ndash190Beaulieu JM Tank DC amp Donoghue MJ (2013) A

Southern Hemisphere origin for campanulid angiosperms

with traces of the break-up of Gondwana BMC Evolution-

ary Biology 13 1

Berger BA Kriebel R Spalink D amp Sytsma KJ (2016)

Divergence times historical biogeography and shifts in

speciation rates of Myrtales Molecular Phylogenetics and

Evolution 95 116ndash136Bloom DD Fikacek M amp Short AEZ (2014) Clade age

and diversification rate variation explain disparity in spe-

cies richness among water scavenger beetle (Hydrophili-

dae) lineages PLoS ONE 9 e98430

Bukontaite R Miller KB amp Bergsten J (2014) The utility

of CAD in recovering Gondwanan vicariance events and

the evolutionary history of Aciliini (Coleoptera Dytisci-

dae) BMC Evolutionary Biology 14 5

Cai L Xi Z Peterson K Rushworth C Beaulieu J amp

Davis CC (2016) Phylogeny of Elatinaceae and the tropi-

cal Gondwanan origin of the Centroplacaceae (Malpighi-

aceae Elatinaceae) clade PLoS ONE 11 e0161881

Drummond AJ Suchard MA Xie D amp Rambaut A

(2012) Bayesian phylogenetics with BEAUti and the

BEAST 17 Molecular Biology and Evolution 29 1969ndash1973

Eberle J Fabrizi S Lago P amp Ahrens D (2017) A histori-

cal biogeography of megadiverse Sericinimdashanother story

ldquoout of Africardquo Cladistics in press doi 101111cla12162

Edgar RC (2004) MUSCLE multiple sequence alignment

with high accuracy and high throughput Nucleic Acids

Research 32 1792ndash1797Fikacek M Wedmann S amp Schmied H (2010) Diversifica-

tion of the greater hydrophilines clade of giant water scav-

enger beetles dated back to the Middle

Eocene (Coleoptera Hydrophilidae Hydrophilina) Inver-

tebrate Systematics 24 9ndash22Fikacek M Prokin A Yan E Yue Y Wang B Ren D

amp Beattie R (2014) Modern hydrophilid clades present

and widespread in the Late Jurassic and Early Cretaceous

(Coleoptera Hydrophiloidea Hydrophilidae) Zoological

Journal of the Linnean Society 170 710ndash734Gamble T Bauer AM Greenbaum E amp Jackman TR

(2008) Evidence for Gondwanan vicariance in an ancient

clade of gecko lizards Journal of Biogeography 35 88ndash104Gibbons AD Whittaker JM amp Meurouller RD (2013) The

breakup of East Gondwana assimilating constraints from

Cretaceous ocean basins around India into a best-fit tec-

tonic model Journal of Geophysical Research Solid Earth

118 808ndash822Givnish TJ Millam KC Evans TM Hall JC Pires

JC Berry PE amp Sytsma KJ (2004) Ancient vicariance

or recent long-distance dispersal Inferences about phy-

logeny and South American-African disjunctions in Rap-

ateaceae and Bromeliaceae based on ndhF sequence data

International Journal of Plant Sciences 165 S35ndashS54Hansen M (1999) World catalogue of insects Volume 2

Hydrophiloidea (s str) (Coleoptera) Apollo Books Sten-

strup Denmark

Kamei RG San Mauro D Gower DJ Van Bocxlaer I

Sherratt E Thomas A Babu S Bossuyt F Wilkinson

M amp Biju SD (2012) Discovery of a new family of

amphibians from northeast India with ancient links to


12


Africa Proceedings of the Royal Society B Biological

Sciences 279 2396ndash2401Kass RE amp Raftery AE (1995) Bayes factors Journal of the

American Statistical Association 90 773ndash795Kim SI amp Farrell BD (2015) Phylogeny of world stag bee-

tles (Coleoptera Lucanidae) reveals a Gondwanan origin

of Darwinrsquos stag beetle Molecular Phylogenetics and Evolu-

tion 86 35ndash48Lanfear R Calcott B Ho SY amp Guindon S (2012) Parti-

tionFinder combined selection of partitioning schemes

and substitution models for phylogenetic analyses Molecu-

lar Biology and Evolution 29 1695ndash1701Lavoue S (2016) Was Gondwanan breakup the cause of the

intercontinental distribution of Osteoglossiformes A

time-calibrated phylogenetic test combining molecular

morphological and paleontological evidence Molecular

Phylogenetics and Evolution 99 34ndash43Lomolino MV Riddle BR Whittaker RJ amp Brown JH

(2010) Biogeography 4th edn Sinauer Associated Inc Sun-

derland MA

Longrich NR Vinther J Pyron RA Pisani D amp Gau-

thier JA (2015) Biogeography of worm lizards (Amphis-

baenia) driven by end-Cretaceous mass extinction

Proceedings of the Royal Society B Biological Sciences 282

20143034

Lopez-Fernandez H Arbour JH Winemiller K amp Honey-

cutt RL (2013) Testing for ancient adaptive radiations in

neotropical cichlid fishes Evolution 67 1321ndash1337Luebert F Couvreur TL Gottschling M Hilger HH

Miller JS amp Weigend M (2017) Historical biogeography

of Boraginales West Gondwanan vicariance followed by

long-distance dispersal Journal of Biogeography 44 158ndash169

Matschiner M Musilova Z Barth JM Starostova Z Sal-

zburger W Steel M amp Bouckaert R (2017) Bayesian

phylogenetic estimation of clade ages supports trans-Atlan-

tic dispersal of cichlid fishes Systematic Biology in press

DOI 101093sysbiosyw076

Matzke NJ (2013a) Probabilistic historical biogeography

new models for founder-event speciation imperfect detec-

tion and fossils allow improved accuracy and model-test-

ing Frontiers of Biogeography 5 242ndash248Matzke NJ (2013b) BioGeoBEARS BioGeography with Baye-

sian (and Likelihood) evolutionary analysis in R scripts

University of California Berkeley Berkeley CA Available

at httpCRAN R-project orgpackage= BioGeoBEARS

(Last accessed May 5 2016)

Matzke NJ (2014) Model selection in historical biogeogra-

phy reveals that founder-event speciation is a crucial pro-

cess in island clades Systematic Biology 63 951ndash970McCulloch GA Wallis GP amp Waters JM (2016) A time-

calibrated phylogeny of southern hemisphere stoneflies

testing for Gondwanan origins Molecular Phylogenetics

and Evolution 96 150ndash160Meng HH Jacques FM Su T Huang YJ Zhang ST

Ma HJ amp Zhou ZK (2014) New Biogeographic insight

into Bauhinia sl (Leguminosae) integration from fossil

records and molecular analyses BMC Evolutionary Biology

14 1

Mennes CB Lam VKY Rudall PJ Lyon SP Graham

SW Smets EF amp Merckx SFT (2015) Ancient Gond-

wana break-up explains the distribution of the myco-

heterotrophic family Corsiaceae (Liliales) Journal of

Biogeography 42 1123ndash1136Mertz DF amp Renne PR (2005) A numerical age for the

Messel fossil deposit (UNESCO World Heritage Site)

derived from 40Ar39Ar dating on a basaltic rock frag-

ment Courier Forschungsinstitut Senckenberg 255 67ndash75Meseguer AS Lobo JM Ree R Beerling DJ amp San-

martın I (2015) Integrating fossils phylogenies and niche

models into biogeography to reveal ancient evolutionary

history the case of Hypericum (Hypericaceae) Systematic

Biology 64 215ndash232Miller MA Pfeiffer W amp Schwartz T (2010) Creating the

CIPRES Science Gateway for inference of large phyloge-

netic trees Proceedings of the Gateway Computing Environ-

ments Workshop (GCE) 14 November 2010 pp 1ndash8 NewOrleans LA

Milner ML Weston PH Rossetto M amp Crisp MD

(2015) Biogeography of the Gondwanan genus Lomatia

(Proteaceae) vicariance at continental and intercontinental

scales Journal of Biogeography 42 2440ndash2451Minh BQ Nguyen MAT amp von Haeseler A (2013)

Ultrafast approximation for phylogenetic bootstrap Molec-

ular Biology and Evolution 30 1188ndash1195Nguyen LT Schmidt HA von Haeseler A amp Minh BQ

(2015) IQ-tree a fast and effective stochastic algorithm for

estimating maximum-likelihood phylogenies Molecular

Biology and Evolution 32 268ndash274Pyron RA (2014) Biogeographic analysis reveals ancient

continental vicariance and recent oceanic dispersal in

amphibians Systematic Biology 63 779ndash797R Core Team (2016) R A language and environment for sta-

tistical computing R Foundation for Statistical Computing

Vienna Austria Available at httpswwwR-projectorg

(Last accessed October 19 2016)

Ree RH amp Sanmartın I (2009) Prospects and challenges

for parametric models in historical biogeographical infer-

ence Journal of Biogeography 36 1211ndash1220Ree RH amp Smith SA (2008) Maximum likelihood infer-

ence of geographic range evolution by dispersal local

extinction and cladogenesis Systematic Biology 57 4ndash14Ree RH Moore BR Webb CO amp Donoghue MJ

(2005) A likelihood framework for inferring the evolution

of geographic range on phylogenetic trees Evolution 59

2299ndash2311Ronquist F amp Sanmartın I (2011) Phylogenetic methods in

biogeography Annual Review of Ecology Evolution and

Systematics 42 441

Ronquist F Teslenko M van der Mark P Ayres DL

Darling A Heuroohna S Larget B Liu L

Suchard MA amp Huelsenbeck JP (2012) MrBayes 32


13


efficient Bayesian phylogenetic inference and model

choice across a large model space Systematic Biology

61 539ndash542Schwarz MP Fuller S Tierney SM amp Cooper SJ (2006)

Molecular phylogenetics of the exoneurine allodapine bees

reveal an ancient and puzzling dispersal from Africa to

Australia Systematic Biology 55 31ndash45Seton M Meurouller RD Zahirovic S Gaina C Torsvik T

Shephard G Talsma A Gurnis M Turner M Maus

S amp Chandler M (2012) Global continental and ocean

basin reconstructions since 200 Ma Earth-Science Reviews

113 212ndash270Short AEZ (2010) Phylogeny evolution and classification

of the giant water scavenger beetles (Coleoptera

Hydrophilidae Hydrophilini Hydrophilina) Systematics

and Biodiversity 8 17ndash37Short AEZ amp Fikacek M (2011) World catalogue of the

Hydrophiloidea (Coleoptera) additions and corrections II

(2006ndash2010) Acta Entomologica Musei Nationalis Pragae

51 83ndash122Short AEZ amp Fikacek M (2013) Molecular phylogeny

evolution and classification of the Hydrophilidae (Coleop-

tera) Systematic Entomology 38 723ndash752Tamura K Stecher G Peterson D Filipski A amp Kumar S

(2013) MEGA6 molecular evolutionary genetics analysis

version 60 Molecular Biology and Evolution 30 2725ndash2729Thomas N Bruhl JJ Ford A amp Weston PH (2014)

Molecular dating of Winteraceae reveals a complex biogeo-

graphical history involving both ancient Gondwanan

vicariance and long-distance dispersal Journal of Biogeog-

raphy 41 894ndash904Toussaint EFA amp Condamine FL (2016) To what extent

do new fossil discoveries change our understanding of

clade evolution A cautionary tale from burying beetles

(Coleoptera Nicrophorus) Biological Journal of the Linnean

Society 117 686ndash704Toussaint EFA Fikacek M amp Short AEZ (2016)

India-Madagascar vicariance explains cascade beetle bio-

geography Biological Journal of the Linnean Society 118

982ndash991Toussaint EFA Hendrich L Hajek J Michat MC Pan-

jaitan R Short AEZ amp Balke M (2017) Evolution of

Pacific Rim diving beetles sheds light on Amphi-Pacific

biogeography Ecography in press doi 101111ecog

02195

Trifinopoulos J Nguyen LT von Haeseler A amp Minh

BQ (2016) W-IQ-TREE a fast online phylogenetic tool

for maximum likelihood analysis Nucleic Acids Research

44 W232ndashW235

SUPPORTING INFORMATION

Additional Supporting Information may be found in the

online version of this article

Appendix S1 Taxon sampling used in this study

Appendix S2 Maximum likelihood gene fragment trees

inferred with W-Iq-Tree

Appendix S3 Details of the lsquoBioGeoBEARSrsquo analyses

conducted with the DEC and DEC+j models

BIOSKETCH

Emmanuel FA Toussaint is a Postdoctoral researcher at

the University of Kansas in Lawrence USA His main

research interest focuses on the origin and evolution of bio-

diversity at global and regional scales He combines ecologi-

cal and molecular data to study lineage diversification and

biogeography of insects mainly aquatic beetles and tropical

butterflies Devin Bloom is an assistant professor at Wes-

tern Michigan University in Kalamazoo MI USA His main

research focuses on the biogeography evolution and diversi-

fication of fishes Andrew EZ Short is an associate profes-

sor at the University of Kansas in Lawrence USA His

research focuses on the diversity distribution and evolution

of aquatic beetles particularly in South America

Author contributions EFAT DB and AEZS conceived

the study DB and AEZS contributed the data EFAT

analysed them designed the figures and wrote the article

AEZS made significant comments on and improvements

to the manuscript

Editor Isabel Sanmartın


14


vicariance and dispersal in governing biodiversity assembly

through space and time in the Southern Hemisphere

The tribe Hydrophilini includes some of the most com-

mon and recognizable members of the water beetle family

Hydrophilidae Commonly referred to as the giant water

scavenger beetles the lineage includes some of the largest

aquatic beetles in the world with some exceeding five cen-

timetres in length Members are easily distinguished by a

sharply delimited lsquosternal keelrsquo that is formed by the fusion

and elongation of the meso- and metaventrites The mono-

phyly of the tribe has been strongly supported by cladistic

analyses based both on morphological (Short 2010) and

molecular (Short amp Fikacek 2013) data Taxa within the

Hydrophilini occupy a relatively narrow range of aquatic

habitats preferring open standing waters or the sluggish

margins and side pools of streams and rivers There are cur-

rently seven genera recognized within the tribe all of which

are easily diagnosed by suites of distinct morphological

synapomorphies (Short 2010) However the interrelation-

ships among these genera remain poorly understood

Giant water scavenger beetles are found in all the worldrsquos

biogeographical regions except Antarctica However this

diversity is not evenly distributed the majority of the grouprsquos

200 species are found in tropical regions and South America

alone is home to more than half of the known species (Short

amp Fikacek 2011) The tribe is one of the most fossil-rich

among the Hydrophilidae and its crown age was recently

estimated to be older than 120 million years ago (Ma)

(Bloom et al 2014 Toussaint et al 2016) Consequently

the diversification and biogeographical dynamics of this

lineage have been unfolding since before the breakup of

Gondwana

Using DNA sequence data from four loci and a broad tax-

onomic and geographic sampling we present the most

detailed phylogenetic and biogeographical analyses of the

tribe Hydrophilini to date to (1) infer the evolutionary rela-

tionships within the lineage (2) refine the age of the tribe

and its major clades and (3) reconstruct the biogeographical

history of the tribe to investigate the biogeographical origins

of hydrophiline diversity We specifically aim at testing the

contribution of vicariance versus dispersal in shaping the

biogeography of Hydrophilini

MATERIALS AND METHODS

Taxon sampling

In total 69 species out of approximately 200 described

(Short amp Fikacek 2011 unpublished data) from six of the

seven currently recognized genera were included (the sev-

enth the monotypic Protistolophus is only known from the

holotype collected in Venezuela) (see Appendix S1 in Sup-

porting Information for more details) Within the six genera

taxa were broadly sampled both taxonomically including 10

of the 12 included subgenera and geographically sampling

species from each genus across all biogeographical regions in

which they occur except for Australian representatives of

Hydrobiomorpha Most missing species belong to the genera

Hydrobiomorpha and Tropisternus and within these missing

taxa a large fraction is concentrated in South America Nev-

ertheless we have a good representation of Neotropical taxa

for these genera in our taxonomic sampling and therefore

are unlikely to lack major lineages Additionally missing

Neotropical species are supported as falling within already-

sampled Neotropical clades in Hydrobiomorpha both Old

and New World clades have unique synapomorphies of the

parameres of the male genitalia and have previously been

resolved as reciprocally monophyletic clades (Short 2010)

In Hydrophilus the missing Neotropical species are primarily

members of the subgenus Dibolocelus a lineage endemic to

South America except for one Nearctic species that we have

already included The well-defined genus Tropisternus does

not occur in the Old World and so any missing Neotropical

taxa would group with existing New World lineages There-

fore based on morphological evidence (Short 2010) we are

confident that most of the taxonomic and geographic diver-

sity of the tribe is represented in our sampling therefore

limiting possible biases in biogeographical analyses We

selected several outgroups including multiple representatives

of the sister tribe Hydrobiusini two more distant outgroups

from the tribes Amphiopini and Berosini and a representa-

tive of the closely related family Epimetopidae The selection

of outgroups was based on the most recent phylogenetic

studies of the family Hydrophilidae (Short amp Fikacek 2013

Toussaint et al 2016)

Molecular methods

From the dataset of Short amp Fikacek (2013) we used the

sequences of Hydrochara obtusata Sternolophus marginicollis

Tropisternus affinis T collaris and T lateralis as well as our

selection of outgroups All other Hydrophilini species used

in this study (64 in total) were sequenced de novo from

freshly collected tissues (see Table S1 for more information)

Specimens were preserved in 96 ethanol and kept frozen at

20 degC or below In a few cases pinned museum specimens

were used Total genomic DNA was extracted from legs with

a DNeasy kit (Qiagen Alameda CA USA)

Four gene fragments were amplified a 1764-bp fragment

of 18S rDNA a 696-bp fragment of arginine kinase (ARK) a

1025-bp fragment of 28S rDNA and a 750-bp fragment of

cytochrome oxidase 1 (CO1) Primers polymerase chain

reaction ingredients and thermocycler conditions were iden-

tical to those described in Short amp Fikacek (2013)

Trace files were edited and assembled in Geneious R

805 (Biomatters httpwwwgeneiouscom) All gene frag-

ments were aligned and refined using Muscle (Edgar

2004) as implemented in Geneious with default settings

Final alignments were adjusted by eye The final concate-

nated alignment consisted of 4235 sites Newly generated

sequences are deposited in GenBank under accession num-

bers KY554217-KY554442


2















































































mond et al 2012)






























3


























































RESULTS





















estimation
































4












5





































ternus species

DISCUSSION














































W-Iq-Tree analyses








6



7









































beast analyses






Node

Yule model

(95 HPD)

Birth-death model

(95 HPD)



density


Gene



CO1 001041 000136 001123 000172 001045 000134 001135 000174

ARK 000060 000007 000061 000008 000060 000007 000061 000008

18S 000006 000001 000007 000001 000006 000001 000007 000001

28S 000052 000006 000060 000011 000052 000006 000060 000010









8



9





















extinction
































patterns




























































10





et al (2012)


11





















ACKNOWLEDGEMENTS










to AEZS

REFERENCES















ary Biology 13 1













































strup Denmark






12
















derland MA





20143034





























14 1







































Systematics 42 441





13




































02195




44 W232ndashW235









BIOSKETCH


















to the manuscript



14















































































mond et al 2012)






























3


























































RESULTS





















estimation
































4












5





































ternus species

DISCUSSION














































W-Iq-Tree analyses








6



7









































beast analyses






Node

Yule model

(95 HPD)

Birth-death model

(95 HPD)



density


Gene



CO1 001041 000136 001123 000172 001045 000134 001135 000174

ARK 000060 000007 000061 000008 000060 000007 000061 000008

18S 000006 000001 000007 000001 000006 000001 000007 000001

28S 000052 000006 000060 000011 000052 000006 000060 000010









8



9





















extinction
































patterns




























































10





et al (2012)


11





















ACKNOWLEDGEMENTS










to AEZS

REFERENCES















ary Biology 13 1













































strup Denmark






12
















derland MA





20143034





























14 1







































Systematics 42 441





13




































02195




44 W232ndashW235









BIOSKETCH


















to the manuscript



14


























































RESULTS





















estimation
































4












5





































ternus species

DISCUSSION














































W-Iq-Tree analyses








6



7









































beast analyses






Node

Yule model

(95 HPD)

Birth-death model

(95 HPD)



density


Gene



CO1 001041 000136 001123 000172 001045 000134 001135 000174

ARK 000060 000007 000061 000008 000060 000007 000061 000008

18S 000006 000001 000007 000001 000006 000001 000007 000001

28S 000052 000006 000060 000011 000052 000006 000060 000010









8



9





















extinction
































patterns




























































10





et al (2012)


11





















ACKNOWLEDGEMENTS










to AEZS

REFERENCES















ary Biology 13 1













































strup Denmark






12
















derland MA





20143034





























14 1







































Systematics 42 441





13




































02195




44 W232ndashW235









BIOSKETCH


















to the manuscript



14












5





































ternus species

DISCUSSION














































W-Iq-Tree analyses








6



7









































beast analyses






Node

Yule model

(95 HPD)

Birth-death model

(95 HPD)



density


Gene



CO1 001041 000136 001123 000172 001045 000134 001135 000174

ARK 000060 000007 000061 000008 000060 000007 000061 000008

18S 000006 000001 000007 000001 000006 000001 000007 000001

28S 000052 000006 000060 000011 000052 000006 000060 000010









8



9





















extinction
































patterns




























































10





et al (2012)


11





















ACKNOWLEDGEMENTS










to AEZS

REFERENCES















ary Biology 13 1













































strup Denmark






12
















derland MA





20143034





























14 1







































Systematics 42 441





13




































02195




44 W232ndashW235









BIOSKETCH


















to the manuscript



14





































ternus species

DISCUSSION














































W-Iq-Tree analyses








6



7









































beast analyses






Node

Yule model

(95 HPD)

Birth-death model

(95 HPD)



density


Gene



CO1 001041 000136 001123 000172 001045 000134 001135 000174

ARK 000060 000007 000061 000008 000060 000007 000061 000008

18S 000006 000001 000007 000001 000006 000001 000007 000001

28S 000052 000006 000060 000011 000052 000006 000060 000010









8



9





















extinction
































patterns




























































10





et al (2012)


11





















ACKNOWLEDGEMENTS










to AEZS

REFERENCES















ary Biology 13 1













































strup Denmark






12
















derland MA





20143034





























14 1







































Systematics 42 441





13




































02195




44 W232ndashW235









BIOSKETCH


















to the manuscript



14



7









































beast analyses






Node

Yule model

(95 HPD)

Birth-death model

(95 HPD)



density


Gene



CO1 001041 000136 001123 000172 001045 000134 001135 000174

ARK 000060 000007 000061 000008 000060 000007 000061 000008

18S 000006 000001 000007 000001 000006 000001 000007 000001

28S 000052 000006 000060 000011 000052 000006 000060 000010









8



9





















extinction
































patterns




























































10





et al (2012)


11





















ACKNOWLEDGEMENTS










to AEZS

REFERENCES















ary Biology 13 1













































strup Denmark






12
















derland MA





20143034





























14 1







































Systematics 42 441





13




































02195




44 W232ndashW235









BIOSKETCH


















to the manuscript



14









































beast analyses






Node

Yule model

(95 HPD)

Birth-death model

(95 HPD)



density


Gene



CO1 001041 000136 001123 000172 001045 000134 001135 000174

ARK 000060 000007 000061 000008 000060 000007 000061 000008

18S 000006 000001 000007 000001 000006 000001 000007 000001

28S 000052 000006 000060 000011 000052 000006 000060 000010









8



9





















extinction
































patterns




























































10





et al (2012)


11





















ACKNOWLEDGEMENTS










to AEZS

REFERENCES















ary Biology 13 1













































strup Denmark






12
















derland MA





20143034





























14 1







































Systematics 42 441





13




































02195




44 W232ndashW235









BIOSKETCH


















to the manuscript



14



9





















extinction
































patterns




























































10





et al (2012)


11





















ACKNOWLEDGEMENTS










to AEZS

REFERENCES















ary Biology 13 1













































strup Denmark






12
















derland MA





20143034





























14 1







































Systematics 42 441





13




































02195




44 W232ndashW235









BIOSKETCH


















to the manuscript



14





















extinction
































patterns




























































10





et al (2012)


11





















ACKNOWLEDGEMENTS










to AEZS

REFERENCES















ary Biology 13 1













































strup Denmark






12
















derland MA





20143034





























14 1







































Systematics 42 441





13




































02195




44 W232ndashW235









BIOSKETCH


















to the manuscript



14





et al (2012)


11





















ACKNOWLEDGEMENTS










to AEZS

REFERENCES















ary Biology 13 1













































strup Denmark






12
















derland MA





20143034





























14 1







































Systematics 42 441





13




































02195




44 W232ndashW235









BIOSKETCH


















to the manuscript



14





















ACKNOWLEDGEMENTS










to AEZS

REFERENCES















ary Biology 13 1













































strup Denmark






12
















derland MA





20143034





























14 1







































Systematics 42 441





13




































02195




44 W232ndashW235









BIOSKETCH


















to the manuscript



14
















derland MA





20143034





























14 1







































Systematics 42 441





13




































02195




44 W232ndashW235









BIOSKETCH


















to the manuscript



14




































02195




44 W232ndashW235









BIOSKETCH


















to the manuscript



14


Documents

Cretaceous West Gondwana vicariance shaped … West Gondwana vicariance shaped giant water scavenger beetle biogeography ... subsequent biogeographical evolution is mainly driven by