Ann. Soc. entomol. Fr. (n.s.), 2003, 39 (4) :

Transcription

1 Ann. Soc. entomol. Fr. (n.s.), 2003, 39 (4) : ARTICLE Geolimnichus n. gen., a new apterous forest floor litter Limnichidae from South Africa (Coleoptera) Carles HERNANDO * (1) & Ignacio RIBERA (2) (1) Museu de Ciències Naturals de la Ciutadella, Passeig Picasso, Parc de la Ciutadella, E Barcelona, Spain (2) Departamento de Biodiversidad y Biología Evolutiva, Museo Nacional de Ciencias Naturales, José Gutiérrez Abascal 2, E Madrid, Spain. Résumé Geolimnichus n. gen., un nouveau Limnichidae aptère sud-africain des litières forestières (Coleoptera). Geolimnichus n. gen. et deux nouvelles espèces, G. endroedyi n. sp. et G. coprophilus n. sp., sont décrits de la litière des forêts de la côte du sud-est de la République d Afrique du Sud (Région afrotropicale). Le nouveau genre est apparenté à Limnichus Latreille (largement répandu dans l Ancien Monde), à Limnichoderus Casey (Néotropical) et à Limnichomorphus Pic (Oriental). Les principaux caractères diagnostiques du nouveau genre sont l absence de courtes soies inclinées sur la face dorsale, le bord postérieur du pronotum droit, ainsi que les caractères des genitalia femelles. Les espèces de Geolimnichus n. gen. possèdent un certain nombre de caractères typiques des espèces de litière forestière, tels la taille réduite, la forme quasi hémisphérique, l absence d ailes métasternales et les yeux réduits. Abstract Geolimnichus n. gen. and two new species, G. endroedyi n. sp. and G. coprophilus n. sp. are described from forest litter in the south Eastern coastal region of the Republic of South Africa (Afrotropical Region).The new genus is related to Limnichus Latreille (widely distributed in the Old World), Limnichoderus Casey (Neotropical) and Limnichomorphus Pic (Oriental). Main diagnostic characters of the new genus are the lack of short, recumbent setae in the dorsal surface; posterior margin of the pronotum straight; and the characters of the female genitalia. The species of Geolimnichus n. gen. have some typical characteristics of forest litter species, such as a reduced size, an almost hemispherical shape, lack of metasternal wings and reduced eyes. The Limnichidae fauna of South Africa is virtually unknown. There is only one published record, Afrolimnichus oblongus Delève, 1974, an endemic belonging to a genus with another species in tropical Africa (Delève 1968, 1974). This is the first of a series of studies of the South African limnichids, based mostly on the revision of the collections of the Transvaal Museum of Natural History (TMSA), aimed to revise the genera present in the area (in addition to Geolimnichus n. gen. described here, Limnichus Latreille, Pelochares Mulsant & Rey, Afrolimnichus Delève, Byrrhinus Motschulsky and an undescribed genus close to Pelochares, all of them within subfamily Limnichinae). * Corresponding author. < chernando@wanadoo.es > < deronectes@gmx.net > Accepté le Here we describe the first endemic genus of South African Limnichidae, with two fully terrestrial species showing some of the typical morphological modifications of forest litter species: small, almost hemispherical size, lack of metasternal wings, and reduced eyes (although not microphthalmic). A recently described Neotropical species of Phalacrichus Sharp shows similar habitat and morphology, although in this case it is true microphthalmic and depigmented (Hernando & Ribera, in press, a). There is not much information about the ecology of the species of Limnichidae (Hernando & Ribera in press, b). Most of them seem to be riparian or semiaquatic, although some have intertidal habits (in particular in subfamilies Thaumastodinae and Hyphalinae), and a few species within riparian genera are secondarily terrestrial, mostly inhabiting tropical forests (Ribera & Hernando 1999; Hernando & Ribera 2001 and in 385

2 C. HERNANDO & I. RIBERA press, b). In addition to the new genus described here, only one genus (with two species) is known to be entirely terrestrial, Limnichomorphus Pic (Satô 1966). RESULTS Geolimnichus, n. gen. (figs. 1, 3, 5-12) Type species Geolimnichus endroedyi n. sp. Description Habitus as in figure 1. Body colour black to dark brown; strongly convex dorsally, almost semicircular, flat ventrally. Head almost completely inserted in pronotum; with dense, erect, golden pubescence; surface covered with fine and very dense punctures. Eyes small but well developed; parallel-sided, elongated and protuberant; with a strong carina along upper margin, reaching insertion of antennae. Antennae short, not reaching posterior margin of pronotum; 11-segmented; antennomeres 1-2 very short and enlarged; 3-4 approximately as wide as 2nd, but ca. half its length, slightly asymmetrical; 5-8 cylindrical and increasingly narrower; 9-11 forming a loose club, widest at apex (fig. 5). Pronotum transverse, lateral margins slightly and regularly curved, very finely bordered (fig. 1). Anterior margin concave, with a line of tubercles parallel to anterior margin, approximately as wide as head. Posterior margin straight, slightly curved only at lateral edges, without any modification for insertion of scutellum. Surface covered with fine, erect pubescence, less dense than on head. Punctation fine and sparse; spaces between punctures clearly visible, smooth and shiny, ca. three times wider than punctures. Scutellum small, triangular, narrow. Elytra very convex, covered with sparse, uniform pubescence. Very convex in lateral view; lateral margin almost straight (fig. 3). Punctation irregular, denser than on pronotum, with a very superficial reticulation; surface between punctures shiny. Without sutural stria or any trace of rows of punctures. Shape regularly convex, without any trace of humeral callus (figs. 1, 3); margins finely bordered. Epipleurae short and wide anteriorly, narrowing abruptly in posterior edge of mesosternum, uniformly narrowed to apex (with a slight enlargement in preapical region, corresponding to the elytral locking device). Without any trace of metasternal wings; only a small, undifferentiated bud present. Ventral surface covered with hydrophobous pubescence, with exception of metasternum, metacoxae and first sternite. Prothoracic hypomera transverse, in two different levels separated by a medial transverse carina. Prosternal apophysis short and wide, lateral margins finely bordered, firmly inserted in mesosternum. Metasternal plaque slightly convex, with a shallow medial longitudinal sulcus; with a double punctation, large punctures deep and sparse, small punctures shallower and denser. First three sternites connated; 4th and 5th articulated, covered with a very dense punctation, with a rugose appearance; last sternite without apical emargination; lateral margins of the 2nd and 3rd sternites slightly depressed for reception of metatibiae. Legs short and robust; femora excavated for reception of tibiae, completely covered by pubescence. Last segment of tarsi Figures 1-5 Geolimnichus n. gen., comparative characters. 1, body outline of G. endroedyi n. sp., dorsal view. 2, body outline of Limnichus sp., dorsal view. 3, body outline of G. endroedyi n. sp., lateral view. 4, body outline of Limnichus sp., lateral view. 5, right antenna of G. endroedyi n. sp. A, pronotum shape; B, articulation scutellum-pronotum; C, humeral callus; D, elytral apex; E, elytral margin; F, shape of the elytra. (onychium) approximately as long as the three preceding segments. Outer margin of protibiae with a short row of preapical spines. Sexual dimorphism. Without apparent external sexual dimorphism. Males with articulated, trilobed aedeagus; parameres fine and long, with a ventral longitudinal sulcus, and an enlarged, membranous apex; basal piece longer than parameres, asymmetrical, with a lateral opening. Struts long, parallel, reaching basal opening. Genital segment symmetrical, with short parameres. Apical part of lamina with a group of long setae (figs. 6-9). Ovipositor long, gonocoxites short and strongly acuminate, divergent in the apex, laterally curved (figs ). Struts long, apex elongated, overlapping the base of gonocoxites up to ca. its medial ventral part. Spiculum ventrale elongated, with a long manubrium, Y shaped; apex of two lateral branches expanded in a separate membranous expansion, with a small group of thick setae in apical margin (fig. 12). Comments Geolimnichus n. gen. has to be included in the subfamily Limnichinae as defined by Hinton (1939) and Wooldridge (1975), because of its trans- 386

3 Geolimnichus n. gen. from South Africa verse metacoxa, tarsi with five segments, presence of an oblique carina in the hypomera, and excavated ventral surface for the reception of legs. Within Limnichinae it seems most closely related with the genera Limnichus (Palaearctic, Afrotropical, Oriental and Australian), Limnichoderus Casey (Neotropical) and Limnichomorphus Pic (Oriental) (see below for a differential diagnosis). All four genera have in common the same type of antenna (with antennal segments not moniliform or pedunculate, and with a three-segmented symmetrical loose club); the presence of supraocular depressions for the insertion of the antennal club; a row of preapical spines in the external margin of the protibia; and genital segment with setae in the apex. Distribution The two known species of Geolimnichus n. gen. are found in the southeast of the Republic of South Africa, in the coastal forest of the states of Transkei (Eastern Cape) and Kwazulu-Natal (fig. 13). Ecology According to label data, specimens were found shifting forest litter, in forest humus or in bushbuck (Tragelaphus scriptus, an antilope) excrements. Etymology The generic name is a combination of the Greek name geos = soil and Limnichus. The gender is masculine. Geolimnichus endroedyi n. sp. (figs. 1, 3, 5-6, 8, 10-12) Type locality Ntsubane forest, 31º 27' S, 29º 44' E, Transkei, Republic of South Africa. Type material Male holotype (TMSA): S. Afr., Transkei / Ntsubane forest / S E, ; E-Y: 2593 / forest floor litter / leg. EndrödyYounga. Paratypes (TMSA; Naturhistorisches Museum, Vienna, NMW; The Natural History Museum, London, NHM and the authors collection): 41 exx., same data as holotype; 1 male (TMSA), S.Afr., Transkei / Silaka For. Reserve / S E, ; E-Y: 2592 / forest floor litter / leg. Endrödy-Younga. Description (only diagnostic characteristics are given) Length mm, maximum width mm. Body black. Head punctation less dense, with some smooth spaces between punctures. Pronotum very transverse, general shape very convex. Line of tubercles on anterior margin of pronotum with tubercles well spaced between them, surface between line of tubercles and anterior margin of pronotum wider. Elytral punctation double, well impressed. Metasternum glabrous; longitudinal sulcus well defined; puncturation less marked. Aedeagus and genital segment as in figs. 6 and 8. Female genitalia as in figs Distribution Transkei (Republic of South Africa), forests of Ntsubane and Silaka (fig. 13). Etymology Dedicated, in memory, to Sebastian Endrödy-Younga, who collected most of the specimens of the new genus. Figures 6-12 Geolimnichus n. gen. 6, G. endroedyi n. sp., aedeagus, dorsal view. 7, G. coprophilus n. sp., aedeagus, dorsal view. 8, G. endroedyi n. sp., genital segment, ventral view. 9, G. coprophilus n. sp., genital segment, ventral view. 10, G. endroedyi n. sp., ovipositor, dorsal view. 11, G. endroedyi n. sp., ovipositor, lateral view. 12, G. endroedyi n. sp., spiculum ventrale, dorsal view. 387

4 C. HERNANDO & I. RIBERA Geolimnichus coprophilus n. sp. (figs. 7, 9) Type locality Ingeni forest, 30º 32'-S, 29º 41', Weza, Kwazulu-Natal, Republic of South Africa. Type material Male holotype (TMSA): S.Afr; S.Natal, Weza / Ingeni forest / S E, ; E-Y: 2690 / bushbuck excrement / Endrödy & Klimaszew. Paratypes: 2 exx. (TMSA): same data as holotype; 1 ex. (TMSA): S.Afr; S.Natal, Weza / lower Stinkwood for. / S , ; E-Y: 2686 / sifted forest litter / Endrödy & Klimaszew ; 1 male (TMSA): Z.A.22 / Town Bush / Maritzb.D., Humus / X Description Length mm, maximum width mm. Brown to black. Head punctation very dense, without free spaces between punctures. Pronotum less transverse. Line of tubercles on anterior margin of pronotum with tubercles less spaced, surface between line of tubercles and anterior margin of pronotum narrower. Body shape less convex, more elongated. Elytral punctation double, consisting of poorly defined small punctures and well impressed large punctures. Metasternum pubescent, more convex; longitudinal sulcus poorly defined. Aedeagus and genital segment as in figs. 7 and 9. Distribution Kwazulu-Natal (Republic of South Africa), Ingeni and Stinkwood forests, Maritzburg (fig. 13). Etymology Meaning excrement-loving, for the habits of the holotype. DISCUSSION Geolimnichus n. gen. can be separated from related genera (Limnichus, Limnichoderus and Limnichomorphus) by the following character combination: head with a short Figure 13 Distribution of the known species of Geolimnichus n. gen. Triangles, G. endroedyi n. sp.; squares, G. coprophilus n. sp. clypeus, which is projected forwards (longer and projected downwards in the other genera) (figs. 1-2); labrum short and laterally expanded (larger and quadrangular in the other genera); pronotum transverse, with margins regularly curved (trapezoidal, with straight margins in Limnichus and Limnichoderus) (figs. 1-2, A); base of the pronotum straight (with a deep double sinuation in the other genera) (figs. 1-2, B); pronotum with a transverse row of small tubercles (absent in Limnichus, present in Limnichoderus and Limnichomorphus); dorsal pubescence sparse, with long, erect setae (double pubescence in Limnichus and Limnichoderus; only short pubescence in Limnichomorphus); body shape hemispherical, without any trace of humeral callus (body shape elongated, with a well developed humeral callus in Limnichus and Limnichoderus, more variable in Limnichomorphus) (figs. 1-2, C); lateral margin of the elytra almost straight (with a double sinuation in the other genera) (figs. 3-4, E); body regularly convex in lateral view (acuminated at the apex in Limnichus and Limnichoderus) (figs. 1-2, D; figs. 3-4, F); absence of prosternal sulcus (present in Limnichoderus but not in Limnichus and Limnichomorphus). The male genitalia is similar in the three genera, although there are some differences in the articulation of the parameres with the phallobase. In Geolimnichus n. gen. the apex of the struts of the ovipositor are elongated, covering the base of the gonocoxites, and have a lateral expansion, unlike those of the other genera, which are simple. The gonocoxites are curved and divergent at the apex, while in the other three genera they are straight and convergent at the apex. The apex of the two lateral branches of the spiculum ventrale are expanded in two separate membranous expansions, not fused in a single membranous lamina, as in the other three genera. Some of the diagnostic characters of Geolimnichus n. gen. are typical of forest litter species (small size, very convex shape, apterism), or could be associated to the lack of metasternal wings (e.g. absence of humeral callus, and possibly posterior margin of pronotum straight). As such, they are likely to be highly labile and of low systematic value. However, other structural features clearly distinguish the species of Geolimnichus n. gen. from the species of related genera (shape of clypeus, labrum and pronotum, body pubescence, and structure of the female genitalia). In consequence, and until a detailed phylogeny of the genera of Limnichinae is available, to our understanding the best working hypothesis is to consider the new species described here as the only members of a new genus of Limnichidae, Geolimnichus n. gen. Acknowledgements We are greatly indebted to the late Sebastian Endrödy-Younga, and to Ruth Muller and James Harrison (Transvaal Museum, Pretoria) for providing material for study. 388

5 Geolimnichus n. gen. from South Africa REFERENCES DELÈVE J Contribution à l étude des Dryopoidea. Les Limnichidae d Afrique (Coleoptera Limnichidae). Bulletin et Annales de la Société Royale d Entomologie de Belgique, 104: DELÈVE J Chapter III: Coleoptera: Limnichidae. In: Hanström B., Brinck P., Rudebeck G. (eds.), South African animal life. Results of the Lund University expedition in , Vol. 15, p Stockholm: Swedish Natural Science Research Council. HERNANDO C., RIBERA I Tricholimnichus gen. n. and three new species from Borneo (Coleoptera: Limnichidae). Koleopterologische Rundschau, 71: HERNANDO C., RIBERA I. In press, a Phalacrichus semicaecus n. sp., the first micropterous and microphthalmic forest-litter species of Limnichidae (Coleoptera). Entomological Problems. HERNANDO C., RIBERA I. In press, b Limnichidae. In: Beutel R.G., Leschen, R.A.B. (eds.), Handbook of Zoology, Vol. 3, Berlin: De Gruyter. HINTON H.E A contribution to the classification of the Limnichidae (Coleoptera). The Entomologist, 72: RIBERA I., HERNANDO C Taxonomic revision of the genus Platypelochares Champion (Coleoptera: Limnichidae). Koleopterologische Rundschau, 69: SATÔ M The Limnichid beetles of Japan. Transactions of the Shikoku Entomological Society, 9: WOOLDRIDGE D.P A key to the New World genera of the beetle family Limnichidae. Entomological News, 86:

6