Frolov, A.V. 2013. New and little known species of the genus Orphnus MacLeay (Coleoptera: Scarabaeidae: Orphninae) from the East African Rift. Zootaxa, 3710(3): 297-300.
New and little known species of the genus Orphnus MacLeay (Coleoptera: Scarabaeidae: Orphninae) from the East African Rift
Laboratory of Insect Systematics, Zoological Institute, Russian Academy of Sciences, Universitetskaya nab., 1, 199034 Sankt-Petersburg, Russia. Email: firstname.lastname@example.org
The East African Rift, especially Eastern Arc Mountains, are renown for exceptionally high biodiversity and endemism (Olson & Dinerstein 1998, Burgess et al. 2007). About 20 species of the scarab beetle genus Orphnus MacLeay, 1819 (Coleoptera: Scarabaeidae: Orphninae) were described or recorded from this region (Paulian 1948, Petrovitz 1971) but many of them are still known only from the type series. Orphnus planicollis Petrovitz, 1971, was described from a single male specimen from “Nyassa-Land” with no additional data about this species published until now. Examination of the Orphninae material housed in European museums revealed additional specimens from southern Eastern Arc Mountains, Tanzania, which allowed us to clarify distribution of this rare species and study its sexual dimorphism and variability. In addition, two specimens of a new, putative sister species, O. demeyeri new species, were found in the material from Upemba National Park (south-eastern Democratic Republic of Congo).
The material used for this study was borrowed from the following institutions: Museum of Natural History of Carmagnola, Italy (MCSNC); Museum of Natural History, Prague, Czech Republic (NMPC); Museum of Natural History of Humboldt-Universität, Berlin, Germany (ZMHUB); Museum of Natural History, Geneva, Switzerland (MHNG); and Zoological Museum of University of Copenhagen, Copenhagen, Denmark (ZMUKK). Preparation of specimens follows the common technique used in entomological research. Photographs were taken with a Leica MZ9.5 stereo microscope and a Leica DFC290 digital camera from dry specimens except for internal sac sclerites, which were photographed in glycerol. Partially focused serial images were combined in Helicon Focus software (Helicon Soft Ltd.) to produce completely focused images. Distribution map was prepared with ArcGIS software (ESRI Inc.).
Orphnus planicollis Petrovitz, 1971
Figs. 1, 3, 5, 6, 9, 11
Type material. Holotype, male with a label “Nyassaland” (MHNG).
Additional material. TANZANIA: Iringa Region, Uzungwa Scarp Forest Reserve, above Chita village, 1450 m, 4–9.xi.1984, pitfall traps, N. Scharff leg., 7 males and 5 females (ZMUKK); Iringa Region, Mafinga, 7–19.i.1996, G.Curletti leg., 6 males and 3 females (MCSNC); “Upangwa Dtsch. O. Afr.”, 1 female (ZMHUB); “Deutsch-O.Afrika”, 1 female (ZMHUB).
Female. Differs from male in having protibiae with elongate spur; clypeus without horn; pronotum narrower, feebly depressed on disc and without umbones and medial tubercle.
Variability. Body length of examined specimens varies from 6.5–9.0 mm. Clypeal horn of males varies from very short (wider than long) to 3 times longer than wide. Medial tubercle on pronotum and especially umbones are less developed in some specimens.
Distribution. The species was described from “Nyassa-Land” without more precise locality. The two exact localities known (Uzungwa Scarp Forest Reserve near Chita and Mafinga) are situated in Uzungwa—the southernmost and largest bloc of Eastern Arc Mountains (Burgess et al. 2007). The other locality, Upangwa, refers to the part of Livingstone Mountains south of Uzungwa. Available data suggest that O. planicollis inhabits mid-altitude afromontane forests and is apparently a litter dweller.
Orphnus demeyeri Frolov, new species
Figs. 2, 4, 7, 8, 10, 11.
Type material. Holotype male with the label "Congo belge: P.N.U. Lusinga (1760 m.) 28-xi-6-xii-1947 Mis. G.F. de Witte. 1103a" (NMPC). Paratype male with the same data as the holotype (NMPC).
Description. Holotype, male. Body elongate, convex, shiny (Fig. 2), length 8.5 mm. Color uniformly dark brown, legs and elytra lighter brown. Head: Clypeus wide, with feebly convex anterior margin, rounded laterally, finely bordered. Genae small, not protruding past eyes. Eyes relatively large (width about equal to distance between eye and gula in ventral view). Frontal suture feebly distinct laterally, broadly interrupted in the middle. Clypeus with short, depressed tubercle slightly sinuate apically. Dorsal surface of clypeus and frons almost impunctate. Labrum deeply sinuate in the middle, relatively feebly protruding past clypeus. Pronotum: trapezoidal, with angulate sides, about 1.7 times wider than long, with impressed disc and 2 feebly marked longitudinal umbones aside of the disc, with a conical tubercle in the middle near base. Anterior angles acute; posterior angles obtuse, more or less distinct in dorsal view. Pronotum distinctly bordered on anterior margin and base. Base of pronotum punctate with a row of relatively small rounded punctures (Fig. 4, arrowed). Sides and disc with rounded punctures separated by about 2–3 puncture diameters. Lateral margins with long, sparse, brown setae. Scutellum: shape subtriangular, narrowly rounded apically, small (about 1/20 the length of elytra). Elytra: Surface convex, 1.1 times longer than wide, with humeral umbones. Elytra widest in the middle. Sutural striae feebly distinct, other striae indistinct. Elytra with sparse double punctation, larger punctures separated by 5–10 times their diameter. Wings: fully developed. Legs: Protibiae with shape typical to Orphnus species, with 3 outer teeth. Lateral margin basad of outer teeth not crenulate. Apical spur of protibia absent. Protarsi well developed, about 4/5 length of protibiae. Claws 1/3 length of apical tarsomere. Apical protarsomere slightly longer than tarsomere 3 and 4 combined. Mesolegs and metalegs are similar in shape; metafemora and metatibiae about 1/8 longer than the mesofemora and mesotibiae. Tibiae somewhat triangular with 2 apical spurs, inner margin almost straight, with 1 transverse keel. Upper spur of tibiae as long as two basal tarsomeres. Claws 1/3 length of apical tarsomere. Femora almost impunctate. Abdomen: Abdominal sternites irregularly punctate, pubescent, with sparse, long setae. Sternite 6 medially shorter than sternites 2–5 combined. Pygidium: Surface transverse, irregularly punctate with transverse punctures, pubescent with sparse setae. Aedeagus: with relatively long parameres, tapering apically (Fig. 10). Internal sac without spinules, with a large, curved sclerite (Figs. 7–8).
Paratype. The single male paratype differs from the holotype in slightly larger size of the body (length 9.0 mm).
Diagnosis. Orphnus planicollis and O. demeyeri should be considered as a distinct species group characterized by the shape of the pronotum (with depressed disc and conical tubercle medially near basal margin), relatively long mandibles, and internal sac without spinules but with a large curved sclerite. O. demeyeri differs from O. planicollis in having sparse punctation of pronotum disc (Fig. 1), base of pronotum with relatively small rounded punctures (Fig. 4) as opposed to a row of elongate longitudinal punctures in O. planicollis (Fig. 3), shape of internal sac sclerite (Figs. 5–8), and aedeagus with more curved (in lateral view) and less twisted (in dorsal view) parameres (Figs. 9–10).
Distribution. The new species is so far known from one locality in the Upemba National Park. The area is a part of Mitumba Mountain range and adjacent to the Albertine Rift afromontane forest zone. Lusinga is situated on the plateau with overage altitudes exceeding 1700 m. Vegetation is mostly a grassland but east of Lusinga there are patches of ravine forest where the specimens of O. demeyeri probably originated.
Etymology. The new species is named after Marc De Meyer, a Diptera specialist at the Royal Museum for Central Africa, Tervuren.
I would like to thank Enrico Barbero (MCSNC), Jiří Hájek (NMPC), Johannes Frisch (ZMHUB), Giulio Cuccodoro (MHNG), and Alexey Solodovnikov (ZMUKK) for loan of material. This work was supported by Russian Foundation for Basic Research (grant 13-04-01002-a).
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