Ann. Soc. ElilOmol. Fr. (N.S.), 1998,34 (3) : 253-258. 253

DESCRIPTION OF THE ADULTS AND LARVAEOF A REMARKABLE NEW OULIMNIUS GOZIS

FROM THE ANTI-ATLAS (S.W. MOROCCO)(COLEOPTERA: ELMIDAE)

Carles HERNANDO(*), Ignacio RfBERA(**) & Pedro AGUILERA(*)

(*) Museu de Zoologia, P.O.Box 593, E-08760 Barcelona, Spain(**) The Natural History Museum, Departmentof Entomology,Cromwell Road,

London SW7 SBD, UK

Resume. - Description de I'adulte et des larves d'un extraordinaire OlllimnillsGozis nouveau de I' Anti-Atlas (S.O. Maroc) (Coleoptera: Elmidae). - Les stadesadulte et larvaires d'une nouvelle espece du genre Ouiimnius, O. jaechi, sp. n., deI'Anti-Atlas marocain, sonl decrits. La morphologie externe des adultes est proche decelie de I'espece ibero-marocaine O.filscipes (Reiche). En revanche, I'edeage est trescaracteristique et morphologiquement derive, tres allonge el cylindrique, avec une allu-re genera Ie typique des Dryopidae. Cette morphologie semble etre I'expression extre-me d'une ten dance morphologique trouvee chez des especes nord-africaines voisines,ainsi que dans d'autres groupes de Dryopoidea.

Abstract. - The adults and larvae of a new species of the genus Oulimnus, O. jaechi,sp. n., are described from the Moroccan Anti-Atlas. The external morphology of theadult is closer to the Ibero-Moroccan species O. filscipes (Reiche), although the aedea-gus is highly characteristic and morphologically derived, very elongated and cylindri-cal, with a general dryopid-like appearance. This seems to be the extreme expressionof a morphological trend recognisable in related north African species, as well as inother groups within the Dryopoidea.

The genus Oulimnius Gozis, 1886 is mostly distributed in Europe and north Africa,with one species, O. aegyptiacus (Kuwert, 1890), reaching the Middle East (Sinai), and onespecies in North America, whose relationship with other members of the genus is uncertain(0. latiusculus LeConte, 1866) (OLM!, 1976; BERTHELEMY, 1979). The genus so far has tenknown Palaearctic species, all with a similar external morphology, which, according toBERTHELEMY (1979), form a well defined monophyletic group. The larvae of only threePa1aearctic species (plus that of O. latiusculus, see BROWN, 1972) have been described,those of O. tuherculatus (P. Muller, 1806), O. troglodytes (Gyllenhal, 1827) and O. rivula-ris (Rosenhauer, 1856) (BERTHELEMY & DUCTOR, 1965; see also BERTRAND, 1972 : 489;KLAUSNITZER & RICHOUX, 1996).

In the course of an entomological survey of Morocco a new species of the genus wasfound in two adjacent localities in the Anti-Atlas, and is described below. A large series ofadults was found in association with larvae and exuviae of differing degrees of develop-ment. The absence of any other known species of Oulimnius in the area led us to concludethat these larvae could safely be attributed to the new species.

Manuscrit accepte Ie 1-IX-1998.

254 C. HERNANDO,I.RIBERA& P. AGUILERA

Methods

Larvae and male and female genitalia were mounted in DMHF (dimethyl hydantoine formaldehy-de) and studied with an optic transmission microscope. Drawings of the male and female genitalia weretraced from microphotographs. Larvae are stored in 70% ethanol.

CABCBCCHBCKBCMMCRBCRMNMWMZB

Acronyms used in the text:

ColI. Aguilera, Barcelona.ColI. Boukal, Ceske Budejovice.ColI. Hernando, Barcelona.Coil. Kodada, Bratislava.Coli. Millan, Murcia.Coli. Ribera, Barcelona.ColI. Rico, Madrid.Naturhistorisches Museum, Wien.Museu de Zoologia, Barcelona.

RESULTS

Oulimnius jaechi, sp. n.

Type locality. - Small mountain stream at the head of the Oued Massa, in AssifOumarhouz, 29Q47'53"N 9Q05'99"W, 1,500 m a.s.l., Anti-Atlas, SW Morocco.

Type material. - Holotype male (NMW) : "MOROCCOOued Massa 21.vii.1997 /Assif Oumarhouz 29Q47'53"N 9Q05'99"W / leg. Hernando, Ribera, Aguilera & Millan".-Paratypes : 92 exs, same locality and date as holotype; 50 exs, "MOROCCOOued Ai't-Baha22.vii.1997 / Ai:t-Iftene 29Q50'25"N 9Q01'57"W / leg. Hernando, Ribera, Aguilera &Millan" (2 males, 3 females, NMW; 2 males, 2 females, MZB; 1 male, 1 female, CBC;1 male, 1 female, CKB; 1 male, 1 female, CRM, the rest of the paratypes in CAB, CHB,CMM, CRB).

Description. - 2.3 - 2.5 mm length, 1.0 - 1.1 mm wide. Body black, legs dark brown with palertarsi, palpi and antenna brown. Body form elongate, oval, surface covered by dense, short, robust, recur-ved golden pubescence. Plastron distribution: upper surface of the head; pronotum except the surface bet-ween the carinae; outer surface of the elytra, from the innermost carina to the epipleura; ventral surfacewith the exception of a central strip delimited by sharp carinae covering the central area of the sternumand the first abdominal sternite; femorae; tibiae.

Head partly retractable, spherical, elongated by the clypeus, frontoclypeal suture well impressed,straight. Eyes prominent, well developed.

Pronotum very convex, with a clear trapezoidal shape, with the maximum width at the base, sidesonly slightly curved, serrate, anterior margin much narrower than the base. Lateral angles of the pronotumprominent, well defined. Carina very impressed, strongly sinuated towards the base, much narrowertowards the anterior margin. Surface between the carinae irregularly shagreened.

Elytra parallel-sided, acuminate towards the apex, not strongly convex. Carinae on the 3rd, 5th and8th interstriae well developed, formed by a series of tubercles. First carina with a clear double sinuation.Surface of the disc with the same irregular shagrination as the pronotum. Striae and interstriae wellimpressed.

Ventral sUiface with a pubescence similar to that of the upper surface, with the exception of a gla-brous elongated triangular area in the posterior margin of the metasternum. All ventral sUliace, includingthe epipleura, with small black tubercles, regularly spaced.

Aedeagus extremely elongated, cylindrical, with a general appearance similar to that of Dryopidae(figs 1 and 2). Evenly curved in lateral view, acuminate towards the apex. Base fused, slightly asymme-

Oulimnius nouveau de /' Anti-Atlas marocain 255

trical, very elongated (with approximately 1.5 the length of the median lobe and the parameres), with dis-tinct oblique striae. Median lobe narrow, parallel-sided, with the apex rounded, doubly sinuated in lateralview. Parameres fused at the base, covering the median lobe, with the distal 1/3 long and narrow, situatedbehind the median lobe, with the apex slightly curved, with I to 3 setae in the middle of their length.

Female ovipositor (fig. 3) with the terminal segment elongated, with a small crown of apical sen-silla. Preterminal segment also elongated, with a reduced number of sensilla. Inner basal margin with twoasymmetrical rows of strong denticles. Distal sclerite wide.

3

2

Figs 1 to 3, Oulimnius jaechi, sp. n. - 1, aedeagus in lateral view. - 2, aedeagus in ventral view. - 3, ovipositor ofOulimnius jaechi, sp. n. (traced from photographs). Scale bar: 0.1 mm.

Description of the larvae. - The description is based on five larvae found in the type locality(Assif Oumarhouz), one apparently fully developed, strongly pigmented, and four smaller and paler, pluseight immature larvae and three exuviae found in Ai't-Iftene. Two immature larvae and one exuvium fromAi't-Iftene are deposited in the NMW, the rest of the material is deposited in the authors' collections.

Full developed larva. Total length 3.3 mm. Dark brown. Posterior margin of the thoracical andabdominal segments with a row of setiferous forked humps, with the ones at the extremes and the two inthe middle longer and broader than the rest, the last two with a small tubercle in between them (fig. 4).Setae of the humps short. Lateral margins of all segments strongly denticulate along their entire length,with very prominent and uniform denticles (fig. 5). Entire surface covered by small tubercles, uniformlyand densely distributed, and with irregularly distributed, asymmetrically forked, setiferous humps. Withtwo central parallel series of setiferous humps, and a basal row of setiferous pores.

256 C. HERNANDO, I.RIBERA & P. AGUILERA

Last abdominal segment wider near base, with almost straight margins convergent at the apex(figs 6 and 7). Ventral margin in lateral view straight, dorsal margin convex, with the maximum depth inthe basal third. With a latera] row of setigerous tubercles. Dorsal and lateral setae with the typical dispo-sition of the genus (see BERTHELEMY& DUCTOR,1965). Surface densely and uniformly covered by smalltubercles, with the exception of the apex, in which they are less dense and prominent. Setiferous humpsof the margins very well developed, forming a series of prominent tubercles reaching 2/3 of the length ofthe IX segment. Apex with the margins irregularly serrate, with long lateral setae. Dorsal carina with a row

A

Pigs 4 to 7, larvae of Oulimnius jaechi, sp. n. - 4, central area of VII abdominal segment, dorsal view. - 5, margin ofVII abdominal segment, dorsal view. - 6, IX abdominal segment, dorsal view. - 7, IX abdominal segment, late-ral view. Scale bars: A (figs. 4 and 5), 0.1 mm; B (figs. 6 and 7) 0.5 mm.

of large setiferous forked humps, irregularly aligned at the base, more regular at the apex. With pointed(not forked) smaller setiferous humps irregularly distributed on the dorsal and lateral sides, with the excep-tion of the apex. Ventral side covered with tubercles only.

Apex of the IX abdominal segment moderately concave, with a row of truncated tubercles alongits posterior margin.

Oulimnius nouveau de I'Anti-Atlas marocain 257

Immature larvae ranging from 1.75 to 2.55 mm. Paler in colour, with the humps and the tuberclesless developed, although still covering all the surface. With less lateral and dorsal denticles and setiferoushumps, which are however still clearly visible, in particular the setiferous hump at the extremes of the pos-terior row in each segment.

Distribution. - So far known from two nearby localities in the West Anti-Atlas,Morocco, on the head of the river Massa (Assif Oumarhouz) and the head of the river Ait-Baha (Ai't-Iftene, 1,350 m a.s.!.), a tributary of Oued Massa.

Ecology. - The two known localities of O. jaechi, sp. n. are mountain streams overrocky calcareous substrata, with filamentous green algae or no aquatic vegetation.Specimens were found in numbers in residual deep (> 1m),Pools with gravel. Conductivity151 µS, pH 9.5 (Assif Oumarhouz); and 215 µS, pH 8.1 (Ait-Iftene).

Etymology. - Named after our friend Manfred A. Jach.

DISCUSSION

The external morphology of O. jaechi, sp. n. is similar to other Palaearctic speciesof the genus, being apparently most closely related to O. Juscipes (Reiche), and O. aegyp-tiacus (Kuwert), both found in North Africa (BERTHELEMY,1979), and the former alsobeing found in the south of the Iberian Peninsula (RICO,1997). A clear diagnostic charac-ter is the short, strong and erect pubescence of both the dorsal and the ventral surface ofO. jaechi, sp. n., not found in any other species of the genus. The morphology of the aedea-gus is however exceptional, with an extremely characteristic dryopid-like appearance(which is obviously homoplasic). Although the basic features of the Oulimnius aedeagusare clearly recognisable, its extreme elongation, its cylindrical and compact shape, thefusion of the basal piece and the base of the parameres, and the position of the apex of theparameres (close behind the median lobe) makes it unique among the genus, even amongthe whole family Elmidae.

According to the phylogenetic arrangement of the genus proposed by BERTHELEMY(1979), and based exclusively on the morphology of the genitalia, O. jaechi, sp. n. wouldbe a basal offshoot, not directly related to any other species. This new species seems howe-ver to be the extreme expression of a morphological trend (general elongation and cylin-drical shape of the male genitalia) which seems to have arisen independently several timeswithin the Dryopoidea, including Limnichidae, as in some Oriental species of the genusPseudeucinetus Heller (SPANGLER,1995). Thus, although much less developed, the aedea-gus of O. Juscipes, and to a lesser extent that of O. aegyptiacus, have some of the featuresof this trend : general compact appearance, base elongated, reduced parameres with theapex close to the median lobe.

The ovipositor has a less deviating morphology, although the extremely strong den-ticles on the inner margin of the preterminal segment are a clear diagnostic character.

The very incomplete knowledge of the larvae of Oulimnius makes the discussion ofthe affinities with the Iberian and north African species impossible. Among the describedPalaearctic larvae, a number of characters place O. jaechi closer to O. rivularis than toO. tuherculatus or O. troglodytes. Thus, in both species the whole dorsal surface is cove-red by tubercles, the two medial setiferous humps of the posterior margin of the abdominalsegments are longer than the marginal ones, and they have a smaller tubercle in the midd-le (BERTHELEMY& DUCTOR,1965; KLAUSNITZER& RICHOUX,1996). The shape of the IXabdominal segment is also similar in both species, although in O. jaechi, sp. n. the dorsalmargin is more convex.

258 C. HERNANDO, I. RIBERA & P AGUILERA

Acknowledgements. - We thank Manfred A. Jach and Andres Millan for their help with the study of thisnew species. We also thank Eugenio Rico for providing us with material for comparison, David Bilton forreviewing the manuscript, and Franck Bameul for translating the summary and for his comments.

LITERATURE CITED

BERTHELEMY c., 1979. - Elmidae de la region palearctique occidentale: systematique et repartition (Coleoptera:Dryopoidea). - Annales de Lil11nologie, 15 : 1-102.

BERTHELEMY C. & DUCTOR M., 1965. - Taxonomie 1arvaire et cycle biologique de six especes dEwllls etd'Oulil11l1ius europeens (Coleoptera Dryopoidea). - Annales de Lil11l'1ologie,1 : 257-276.

BERTRAND H., 1972. - Lanes el nymphes des coltopteres aquatiques du globe. Paris: F. Paillart, 804 p.BROWN H. P., 1972. - Biota of freshwater ecosytems identification manual No.6, Aquatic Dryopoid beetles

(Coleoplera) of the Uniled Slales. Washington: U. S. Environmental Protection Agency, 82 p.KLAUSNITZER B. & R1CHOUX P.. 1996. - 40. Familie : Elmidae. In : Klausnitzer, B. (ed.), Die Larven del' Kafer

Milleleuropas, 3 : 112-143.OLMI M., 1976. - Fauna d'italia. Coleoplera. Dryopidae - £Iminlhidae. Bologna: Edizioni Calderini, 280 p.RICO E., 1997. - Distribuci6n de los Elmidae (Coleoptera: Dryopoidea) en la Peninsula Iberica e Islas Baleares. -

Graellsia, 52 (1996): 115-147.SPANGLER P. J., 1995. - A review and two new species of the genus Pseudeucilletlls Heller from Southeast Asia and

a World checklist of the Thaumastodinae (Coleoptera, Limnichidae). - Special issue. Bullerin of rhe JapaneseSociely of Coleopterology, [Tokyo], 4 : 395-495.