SYSTEMATICS, PHYLOGENY AND FLORISTICS

New planktic species of Kirchneriella Schmidle (Chlorophyceae,Selenastraceae) from Brazilian freshwaters

Daniella da Silva • Celia L. Sant’Anna •

Andrea Tucci • Augusto Comas

Received: 30 July 2012 / Accepted: 1 April 2013 / Published online: 16 July 2013

� Botanical Society of Sao Paulo 2013

Abstract New planktic species of Kirchneriella Schm-

idle (Chlorophyceae, Selenastraceae) from Brazilian

freshwaters. In the samples collected from an artificial lake,

located in the metropolitan region of Sao Paulo, an inter-

esting algal population morphologically similar to Kirch-

neriella Schmidle was found. The crescent-shaped cells

were oriented, inside the colony, with their convex faces

toward the periphery of the colony resembling those of K.

roselata Hindak. However, the remaining portions of the

mother cell wall with more or less radial arrangement

similar to the connective mucilaginous threads of the genus

Selenodictyon Uherkovich & Schmidt ex Comas & Ko-

marek were also observed. After further studies based on

light microscope, the studied material proves to be mor-

phologically distinguishable from K. roselata, although it

never forms rosette-like groups, which are typical in K.

roselata. The remaining parts of the mother cell wall more

or less radially disposed near the cells (autospores just

released from the mother cell wall) are not connective

threads. Thus, a new species, K. brasiliana, is described in

this paper. According to literature, the main diagnostic

feature of Selenodictyon is the crescent-shaped cells

attached by their concave faces to mucilaginous stalks like

in Dictyosphaerium; however, remaining portions of the

mother cell wall more or less radially oriented were also

formed in some Kirchneriella populations. Therefore, the

authors consider that such feature could be misinterpreted

as connective mucilaginous threads, which raises doubts

regarding the validity of Selenodictyon.

Keywords Green algae � Fish pound � New species �Taxonomy

Introduction

Kirchneriella Schmidle 1893 was traditionally included in

the families Ankistrodesmaceae (Korsikov 1953), Chlo-

rellaceae (Komarek and Fott 1983), or in Selenastraceae

(Marvan et al. 1984), belonging to Chlorococcales. Recent

studies based on gene sequence analysis (Krienitz et al.

2001) show phylogenetic relationships with Sphaeropleales

sensu Deason et al. (1991). These studies also showed that

the family Selenastraceae constitutes a monophyletic group

belonging to the class Chlorophyceae (Krienitz et al. 2011).

In spite of the fact that the morphological features do not

correspond to molecular basis for distinguishing genera in

the Selenastraceae (Fawley et al. 2005), the genus Kirch-

neriella, in the traditional sense (as genus forma), is well

characterized by arcuate, crescent-shaped, or cylindrical-

fusiform (irregularly curved) and even sigmoid cells, dis-

posed in colonial mucilage. The cell ends are sharp, pointed

round, pointed, or round. The cells inside the colony can be

organized with their convex side turned to the colony center

or turned to the colony edge. The parietal chloroplast occu-

pies a large portion of the cell volume and pyrenoids may be

present or not. Reproduction occurs by autospores disposed

in series inside the mother cell wall or, more rarely, more or

less in parallel arrangement. Autospores are liberated by the

rupture of the mother cell wall, which later will be com-

pletely or partially gelatinized. In this last case, the remnants

of the mother cell wall remain inside the colonial mucilage.

D. da Silva � C. L. Sant’Anna (&) � A. Tucci

Instituto de Botanica, Nucleo de Pesquisa em Ficologia,

Sao Paulo, SP, Brazil

e-mail: celialsant@yahoo.com.br

A. Comas

Centro de Estudios Ambientales de Cienfuegos, Ministerio de

Ciencias, Tecnologıa y Medio Ambiente, Cienfuegos, Cuba

123

Braz. J. Bot (2013) 36(2):153–157

DOI 10.1007/s40415-013-0014-5

The presence or absence of the pyrenoid (under the light

microscope) was traditionally considered a good diacritic

feature, allowing the classification of species into two

independent genera: (1) Kirchneriella s. str., with pyrenoid

(type species K. obesa (W. West) Schmidle 1893); (2)

Pseudokirchneriella Hind. 1990, without pyrenoid (=Kir-

chneria Hindak 1988, Raphidocelis Hindak 1977 sensu

Marvan et al. 1984).

There is no precise designation of the type species of

Pseudokirchneriella, and for this reason we are considering

Pseudokirchneriella subcapitata (Korsikov) Hindak 1990

as a type species, based on the fact that Kirchneria, whose

type species is K. subcapitata (Hindak 1988), is considered

to be synonymous with Pseudokirchneriella.

According to molecular studies (Krienitz et al. 2001;

Krienitz and Bock 2012), small genera based only on

morphological features are not sustainable, and the

adoption of only one genus (Kirchneriella) in broad sense

could be the correct option. Other features such as the

presence or absence of a pyrenoid, single cells or in col-

onies, and autospores arrangement inside the mother cell

wall are not enough to distinguish the mentioned genera

separately.

In the samples collected from an artificial lake, loca-

ted in the metropolitan region of Sao Paulo City, Brazil,

an interesting algae, morphologically similar to Kirch-

neriella roselata Hindak, was found. The cells are ori-

ented with their convex faces toward the periphery of the

colony and after reproduction (autospores liberated by

rupture of mother cell wall), the remnants of the mother

cell walls remain more or less radially oriented inside

the colonial mucilage looking like connective mucilagi-

neous stalks similar to those of Selenodictyon brasiliense

Uherkovich & Schmidt ex Comas & Komarek. This

algal population was studied in order to reach its accu-

rate taxonomical definition and clarify its relations to

other similar taxa.

Materials and methods

The studied populations were collected from an artificial

lake used for fishing (some limnological parameters are

shown in Table 1), located in the City of Suzano, Sao

Paulo State, southeastern Brazil (S23�2502400 W46�2200500).The samples were obtained using van Dorn’s bottle

and plankton net (20 lm), in dry and rainy seasons in a

year.

The samples were preserved with 4 % formaldehyde

and studied in a Zeiss Axiosplan 2 microscope. China ink

was used to improve the mucilage observation. The clas-

sification systems of Komarek and Fott (1983) and Krienitz

et al. (2001) were adopted.

Results and discussion

Kirchneriella brasiliana sp. nov.

Diagnosis: Coloniae libere natantes, irregulariter sphaericae

usque ovales, multicellulares, praecipue per turmas 2–4

cellulares aggregatas circum superficiem coloniae formatas,

cum latis concavis ad centrum coloniae dispositae. Tegu-

mentum gelatinosum, homogeneum, tenues, hyalinum, sine

structura. Cellulae fusiformes, arcuatae, moderate contor-

tae, ad utrosque polos aequaliter angustatae, apicibus acutis.

Membrana cellularia levis, hyalina. Chloroplastum unum,

parietale, sine pyrenoide. Propagatio 2–4 autosporis; auto-

sporae e membrana matricali divisione centrali in partes

duas liberantur; frequenter vestigia membranae matricali

circa cellulae juveniles remanens, ut videtur similis con-

nectivis, re vera autem, e cellulis distantibus. Dimensiones

cellularum: 11.3–17.0 9 1.2–3.1 lm.

Habitatio (locus classicus): in plancto lacus, Suzano,

Brasilia.

Holotypus: Brazil, Sao Paulo State: Suzano, 12-III-

2002, D Silva s.n. (SP3913443).

Description

Kirchneriella brasiliana sp. nov. (Fig. 1)

Colonies free floating, rounded to ovoid, formed by groups

of 2–4 cells arranged in the colony periphery; cells lunate,

pointed at both ends, concave side turned to the center of

Table 1 Physical, chemical, and biological variables of the studied

lake, Sao Paulo State, Brazil (according to Mercante et al. 2004,

2005)

Variables Collecting

Dry season Rainy season

Water temperature (�C) 21.9 30.0

Deep (m) 1.0 1.0

Euphotic zone (m) 0.6 0.6

Conductivity (lS cm-1) 30.0 30.0

pH 5.8 5.6

Dissolved oxygen (mg L-1) 6.1 11.0

Turbidity (NTU) 78.0 72.0

N–NO2- (lg L-1) 7.0 9.1

N–NO3- (lg L-1) 58.3 45.5

N–NH4? (lg L-1) 86.0 29.0

P–PO4- (lg L-1) 27.5 14.5

PT (lg L-1) 161.7 162.3

Chlorophyll a (lg L-1) 68.7 106.5

Trophic state index 69 69

154 D. da Silva et al.

123

colony; mucilaginous envelope thin, difluent; chloroplast

parietal, without pyrenoid; reproduction by autospores;

remaining parts of the mother cell wall in the center of the

colony, displaying radial orientation near the cells. Cells

length: (11.3–) 14.7 lm (–17). Cells diameter: (1.2–)

2.0 lm (–3.1).

Locality: Brazil, Sao Paulo, Municipality of Suzano,

fish-pond, plankton material, 08-X-2001 (dry season),

D Silva s.n. (SP3913442); 12-III-2002 (rainy season),

D Silva s.n. (SP391343).

The Brazilian material is morphologically similar to

K. roselata described from Eslovaquia (Hindak 1984), and

also registered in Ukraine (Tsarenko 1990) and Bulgaria

(Stoyneva 1998). K. roselata is an infrequently observed

species in the plankton of waters with different trophic

conditions (Stoyneva 1998). However, this taxon is

characterized by cells sharply curved, thin, normally joined

at one end, forming rosette-like groups, which present their

concave faces toward the center of the colony. When

they are present, remnants of the mother cell wall, par-

tially gelatinized, are scarce and spread without a radial

disposition.

Actually, the studied material is morphologically related

to this species, but the cells of the studied colonies never

form rosette-like groups, which are typical in K. roselata

and remnants of the mother cell wall, more or less radially

oriented in colonial mucilage, are usually present.

The Brazilian population is also similar to Selenodictyon

brasiliense when considering the orientation of the cells in

the colony, but in particular, because of the remaining

portions of the mother cell wall that present more or less

radial disposition near the cells (autospores just released).

Fig. 1 Kirchneriella brasiliana. 1, 2 General aspect of the colonies showing the cells disposition. 3 Detail of mother cell wall rests radially

disposed (arrow). 4 Scheme of one colony with mother cell wall rests (arrow). Bar 10 lm

New planktic species of Kirchneriella 155

123

However, they are not connective threads which are

obligatory in Selenodictyon, according to its diagnosis

(Comas and Komarek in Comas 1992).

Considering all taxonomical characteristics of the

studied population, we concluded that the material could be

considered as an independent species of Kirchneriella

(Table 2 shows the main morphological features of the

species compared with other related taxa).

Due to the similarity of the new species with S. brasiliense,

some taxonomic comments are necessary: the genus Sele-

nodictyon, with its type species S. brasiliense, was pub-

lished improperly by Uherkovich and Schmidt (1974)

(nom. nud.), based on plankton samples from Lago Cas-

tanho, in the State of Amazon, north of Brazil.

Supported by the work of van der Heide (1982) based on

samples from Lake Brokopondo, Suriname, as well as by

materials from Cuba that could correspond to Selenodict-

yon, Comas and Komarek (Comas 1992) validated the

genus Selenodictyon. With another concept, they grouped

in this genus some species with elongated to crescent-

shaped cells, two or more times longer than wide, attached

by their concave faces to mucous filiform stalks similar to

those of Dictyosphaerium Nageli. The species have one

parietal chloroplast with or without pyrenoid. Selenodictyon

brasiliense presents pyrenoid, according to the illustration of

Uherkovich and Schmidt (1974).

According to this conception, the genus Selenodictyon

was represented by three species: S. brasiliense, S. navicu-

liforme Comas & Komarek and S. elongatum (Hindak)

Comas & Komarek.

Taking into account the presence of Kirchneriella popu-

lations in materials from Cuba and Mexico (Veracruz), in

which crescent-shaped cells are disposed similarly to those

of Selenodictyon, with remaining portions of the mother

cell wall more or less radially disposed inside the colonial

mucilage, which could be misinterpreted as connective

threads similar to Dictyosphaerium/Selenodictyon, Comas

and Perez Baliero (2002) pointed out serious doubts in

relation to the existence of the genus Selenodictyon,

keeping, ‘‘ad interim’’, only one species: S. brasiliense.

According to the authors, the other Selenodictyon species

were not justified.

After our observations in Brazilian samples from Sao

Paulo State, we also consider that Selenodictyon is not a

good genus, and possibly it could be a particular species of

Kirchneriella s.l., whose cells’ concave face is disposed

toward the center of the colony. The remnants of the

mother cell wall, which are radially disposed inside the

Table 2 Comparison of the diacritic features of K. brasiliana and related species of the genera Selenodictyon and Kirchneriella

Selenodictyon

brasiliense

Uherk. &

Schmidt

(Uherkovich and

Schmidt 1974)

Selenodictyon

brasiliense

Uherk. &

Schmidt

(Komarek and

Fott 1983)

Selenodictyon

brasiliense

(Uherk. and

Schmidt) Com. &

Kom. (Comas

1992)*

Kirchneriella roselata

Hind. (Hindak 1984)

Kirchneriella

irregularis G.M.

Smith (Korsikov

1953)

Kirchneriella

brasiliana sp.

nov.

Cell form Lunate, pointed at

both ends

Lunate, pointed at

both ends

Lunate, pointed at

both ends

Fusiform, curved, slightly

sigmoid

Fusiform,

curved,

regularly

attenuated to

the bluntly

rounded or

obtuse ends

Lunate, pointed at

both ends

Cells

distribution

in the

colony

Groups of 2–4

cells arranged

in the colony

periphery;

concave side

turned to the

center of colony

Groups of 2–4

cells arranged

in the colony

periphery;

concave side

turned to the

center of colony

Groups of 2–4

cells arranged

in the colony

periphery;

concave side

turned to the

center of colony

Groups of 2–4 cells with

their ends close to each

other, forming rosette-

like groups; concave

side of the cells turned

to the center of colony

Groups of 4 cells

irregularly

disposed in the

mucilage; cells

with the

convex side

outwards

Groups of 2–4

cells arranged

in the colony

periphery;

concave side

turned to the

center of colony

Chloroplast

and

pyrenoid

_ Chloroplast

parietal with

one pyrenoid

(according to

the figures)

Chloroplast

parietal with

one pyrenoid

Chloroplast parietal

without pyrenoid

Chloroplast

parietalprobably with

one pyrenoid

Chloroplast

parietal without

pyrenoid

Cell length 6.5–7.0 lm 6.5–7.0 lm 6.5–7.0 lm 7.5–12 lm 6.0–21.0 lm (11.3) 14.7 lm

(17.0)

Cell wide 1.5 lm 1.5 lm 1.5 lm 1.5–2.0 lm 3.0–6.0 lm (1.2) 2.0 lm (3.1)

Mucilage _ Thin, hyaline Thin, hyaline Homogenous, hyaline _ Thin, hyaline

* Valid publication according to Botanical Code of Nomenclature

156 D. da Silva et al.

123

colony, must have been erroneously considered as con-

nective threads by Uherkovich and Schmidt (1974) and

Comas and Komarek (Comas 1992).

However, it is not possible to transfer S. brasiliense to

the genus Kirchneriella as a new combination because the

holotype of S. brasiliense is just a figure (Uherkovich and

Schmidt 1974, Taf. IV, Fig. 84), in which it is possible to

observe cells attached to the mucilaginous threads. As there

is no preserved sample of S. brasiliense, it is not possible to

confirm whether these ‘‘mucilaginous threads’’ were mis-

interpreted. Because of that and the presence of pyrenoids

in Fig. 84 that never occur in the material from Sao Paulo

State, it is impossible to consider S. brasiliense as a syno-

nym of K. brasiliana. The real taxonomic position of

S. brasiliense will be defined only if other populations are

found again.

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