Frolov, A.V., Montreuil, O. 2009. A new genus of Orphninae (Coleoptera, Scarabaeidae) from Madagascar. Zoosystematica Rossica, 18, 65-69.

A new genus of Orphninae (Coleoptera, Scarabaeidae) from Madagascar

A.V. Frolov1 & O. Montreuil2

1Laboratory of Insect Systematics, Zoological Institute, Russian Academy of Sciences, Universitetskaya nab., 1, 199034 Sankt-Petersburg, Russia. E-mail: aphodius@rambler.ru

22UMR 602, Department of Systematics and Evolution, National Museum of Natural History, Entomology, CP 50, 45 rue Buffon, 75231 Paris cedex 05, France. E-mail: o.montr.@mnhn.fr

Abstract

A new genus, Renorphnus gen. n, is established for Madagascar species Orphnus clementi Petrovitz. The new genus differs in distinctive shape of anterior tibiae of male, shape of clypeus, pronotum with 2 more or less prominent tubercles in both sexes, and in widened and pectinate setae on costal margin of wings. O. clementi is redescribed. Diagnostic key to Madagascar Orphninae genera is given.

Key words: scarab beetles, Renorphnus gen. n., taxonomy

Introduction

Scarab beetles of the subfamily Orphninae occurring in Madagascar have long been recognized as a unique and taxonomically diverse group (Paulian 1937, 1977, 1992). All the described species are endemic to the island. Most of them belong to the three genera also endemic to Madagascar, namely Triodontus Westwood, 1846, Pseudorphnus Benderitter, 1913, and Madecorphnus Paulian, 1992. But one rare Madagascar species, Orphnus clementi Petrovitz, 1971, was originally placed in the large Afro-Asian genus Orphnus Macleay, 1819. This species was so far known from one male specimen. In the past years, however, reasonable number of specimens of both sexes was collected by Finish colleagues and provided to us. Examination of this material as well as the holotype showed that the species does not share diagnostic characters of the genus Orphnus, nor does it fit diagnoses of the three known Madagascar genera. A new genus is therefore established for it.

Habitus photographs were taken with a Leica MZ12 stereo microscope and photographs of aedeagi, internal sacs, and wing were taken with a Leica DMLB compound microscope from specimens in glycerol. Partially focused serial images were combined in Helicon Focus software (Helicon Soft Ltd.) to produce completely focused image. Distribution map was generated with ArcGIS software (ESRI Ltd.). Coordinates of the localities were taken with a GPS receiver (majority of localities) or from the NGA GEOnet Names Server (GNS, http://earth-info.nga.mil/gns/html/index.html).

The material used for this study is housed in the following institutions: MHNG: Natural History Museum, Geneva; MNHN: Natural History Museum, Paris; UHHF: University of Helsinki; ZIN: Zoological Institute of Russian Academy of Sciences, Sankt-Petersburg.

Renorphnus gen. n.

Type species Orphnus clementi Petrovitz, by monotypy.

Diagnosis

Medium-sized beetles with uniform brown coloration. Clypeus symmetrical, wide, somewhat emarginate anteriorly, with risen anterior margin somewhat tuberculate in males. Mandibles subsymmetrical, of the same length. Head smooth. Frontal tubercles absent. Pronotum wider than long, smooth, lateral margins crenulate, with long sparse setae. Disc of pronotum similar in both sexes, with shallow, sometimes almost indistinct depression anteriorly and 2 small tubercles aside the depression. Elytra with only first stria distinct. Wings fully developed, costal margin with apically widened and pectinate setae. Anterior tibiae of males with apical outer tooth directed almost parallel to the inner margin of tibia. Parameres symmetrical.

Figs 1-5. Renorphnus clementi. 1, 2 – general view (1 – male, 2 – female); 3 – parameres in dorsal view; 4 – aedeagus in lateral view; 5 – internal sac of aedeagus.

Figs 1-5. Renorphnus clementi. 1, 2 – general view (1 – male, 2 – female); 3 – parameres in dorsal view; 4 – aedeagus in lateral view; 5 – internal sac of aedeagus.

From the members of the genus Orphnus, it differs in the distinctive shape of the anterior tibiae, shape of the clypeus, and pronotum with 2 more or less prominent tubercles in both sexes. From the other Madagascar genera, Renorphnus gen. n. can be separated by the characters given in the keys below. The peculiar shape of setae on costal margin of wings is not known in other genera and is probably an autopomorphy of Renorphnus gen. n.

Etymology. The new genus is named after Renaud Paulian, whose publications provided sound framework for the taxonomic research on African and Madagascar Orphninae and who supposed that Orphnus clementi should be placed in a separate genus. The genre of the name is masculine.

Renorphnus clementi (Petrovitz), comb. n.

Orphnus (Parorphnus) clementi Petrovitz, 1971: 21; Paulian, 1977: 1201.

(Figs 1-7, 14, 15)

Type material examined. Holotype, male: MADAGASCAR: Ivoloina, Tamatave, Clement leg. (MHNG).

Additional material examined. MADAGASCAR: Andahahelo, wet forest, fish bated trap, I. Hanski group leg., 23.3.2004, 1 male (ZIN), 26.4.2006, 2 males, 2 females (UHHF, ZIN); Forest 25 km W of Morarano-Chrome, 13-25.IV.1991, A. Pauly leg., 1 male and 1 female (MRAC); Andasibe protected area, wet forest, alt. 800 m, fish bated trap, III.2004, I. Hanski group leg., 1 female (ZIN); Ambila, littoral forest, alt. 50 m, fish baited trap, III.2004, I. Hanski leg., 1 female (ZIN); Beza-Mahafaly, Betioky, alt. 140 m., semi-dry eucalypt forest, fish baited pitfall trap, 10.4.2006, I. Hanski group leg., 1 male (ZIN); Ambatotsirongorongo, fish baited trap, II.2005, I. Hanski group leg., 3 males and 1 female (UHHF, ZIN, MNHN); St. Luce, Manafiati, alt. 0 m, humid forest, fish baited pitfall trap, 16.4.2006, I. Hanski group leg., 2 males and 2 females (MNHN, ZIN)

Figs 6-11. Orphninae. 6, 7, 14, 15 - Renorphnus clementi. 8, 9 – Madecorphnus sp. 10, 11 – Triodontus sp.12, 13 – Pseudorphnus sp. 6-13 – anterior tibia (6, 8, 10, 12 – male; 7, 9, 11, 13 – female); 14 – wing costal area; 15 – distribution map.

Figs 6-11. Orphninae. 6, 7, 14, 15 - Renorphnus clementi. 8, 9 – Madecorphnus sp. 10, 11 – Triodontus sp.12, 13 – Pseudorphnus sp. 6-13 – anterior tibia (6, 8, 10, 12 – male; 7, 9, 11, 13 – female); 14 – wing costal area; 15 – distribution map.

Male. Medium-sized beetle with elongated, oval, strongly shiny body (Fig. 1). Color brown, legs and apices of elytra somewhat paler.

Clypeus slightly convex anteriorly, obtusely rounded, anterior margin setose and crenulate in dorsal view. Genae very small, crenulate, not protruding past eyes. Eyes relatively large (diameter larger than the distance between eye and gula in ventral view), incompletely divided by canthus into smaller dorsal and larger ventral parts. Frontal suture absent. Clypeus not tuberculate, with more or less raised anterior margin in the middle; in some specimens it forms a sort of flattened triangular tubercle, although it is never as robust and horn-like as in Triodontus and Pseudorphnus males. Dorsal surface of head impunctate.

Labrum somewhat bilobate, slightly sinuate in the middle and relatively feebly protruding past clypeus. Length in the middle is 1/5 width (in dorsal view).

Pronotum 1.6 times wider than long, widest medially. Anterior margin with wide border, base with fine border. Lateral margins densely punctate, appearing crenulate in dorsal view. Disc of pronotum with shallow, sometimes almost indistinct depression anteriorly, with 2 small tubercles aside the depression. Surface of pronotum smooth, without punctures. Lateral margins with long, brown setae.

Scutellum triangular, narrowly rounded apically, about 1/10 length of elytra.

Elytra convex, with feebly marked humeral umbones. Maximum width approximately at the middle. First stria distinct and reaching the apex of elytron, other striae feebly marked to indistinct. Disc of elytra with sparse punctures. Epipleura with long, sparse, brown setae. Base of elytra bordered.

Wings fully developed.

Anterior tibiae with 3 outer teeth. Apical tooth is directed almost parallel to the inner margin of tibia (Fig. 6). Lateral margin basad of outer teeth not crenulate. Apex and internal margin of tibia with robust, spur-like setae becoming slender towards the base of tibia. Anterior tarsi well developed, about 4/5 length of protibiae. Claws 1/2 length of apical tarsal segment. Apical segment of anterior tarsus as long as segments 3 and 4 combined, as thick as other segments. Ventral surface of anterior tibiae smooth with two rows of setae along sides and sparse longer setae in the middle. Ventral surface of femora smooth.

Middle and posterior legs similar in shape; posterior femora and tibiae about 1/8 longer than middle ones. Tibiae somewhat triangular, with two apical spurs. Longer tibial spur as long as two basal segments of tarsus. Claws 1/3 length of last tarsal segment. Femora almost impunctate, with two rows of long setae.

Abdominal sternites with somewhat granular sculpture. Sternite 6 medially as long as sternites 4-5 combined.

Pygidium transverse, irregularly punctate, hidden under elytra.

Aedeagus. Parameres symmetrical, tapering apically in lateral view and with a minute teeth at very apex (Figs 3, 4). Internal sac with an area composed of small spinules and with 2 characteristic semicircular sclerites (Fig. 5).

Female. In comparison to other Orphninae genera, sexual dimorphism in R. clementi is weak. Females (Fig. 2) are similar to males in shape of pronotum, although they have smaller medial tubercles in overage. Female of R. clementi can however be readily separated from male by a character shared by all orphnins — presence of a long, robust apical spur on anterior tibia (Fig. 7).

Variation. The length of the examined males varies from 8.0 to 8.7 mm, females from 7.0 to 9.5 mm. Most of specimens of both sexes have distinct tubercles on disc of pronotum, although some specimens have feebler tubercles or only traces of them; 2 females from St. Luce have no tubercles, although the males from the same series have distinct tubercles.

Distribution and habitat. Judging from the examined material, Renorphnus gen. n. is widely distributed in Madagascar although it is probably rare in all parts of its range. The beetles were collected in wet forests in the eastern part of the island including littoral forests on the eastern coast and in relatively dry areas with secondary forest in western part of Madagascar. In all cases where the data are available, the beetles were collected with pitfall traps baited with fish. Trapping setup and timing is described in more detail in our paper about Pseudorphnus hiboni (Frolov, Montreuil, 2006). As with the latter species, short-time exposures of the traps suggest that specimens of R. clementi were attracted to the carrion rather than captured accidentally.

Key to the Madagascar Orphninae genera

1. Anterior tibiae with 2 outer teeth apically and one much smaller outer tooth basally (Figs 12, 13) ..... Pseudorphnus

- Anterior tibiae with 3 outer teeth in apical half (Figs 6-11) ..... 2

2. Lateral margin of pronotum with 4 long setae: 2 near anterior margin, 1 in the middle, and 1 near posterior margin. Some or all setae may be abraded, but 4 chaetiferous punctures are always distinct. Left and right mandibles can differ strongly in length in males, and clypeus is somewhat asymmetrical in such cases. Disc of pronotum smooth, without processes or excavations ..... Madecorphnus

- Lateral margin of pronotum with numerous setae (at least more than 10) evenly distributed along the margin; setae may differ strongly in length. Left and right mandibles of about the same length, clypeus symmetrical. Disc of pronotum may be with more or less developed tubercles, ridges and excavations ..... 3

3. Width of eye in dorsal view about 8-10 times smaller than distance between eyes. Propleurae with a longitudinal ridge bearing a row of setae parallel to lateral margin of pronotum. Disc of pronotum with more or less developed tubercles, ridges and excavations in males, and smooth in females. Apical outer tooth of anterior tibia in males directed laterally, at reasonable angle to the internal margin of tibia (Fig. 10) ..... Triodontus

- Width of eye in dorsal view about 3-4 times smaller than distance between eyes. Propleurae without a longitudinal ridge, only with a sparser row of setae. Disc of pronotum with two feebly developed tubercles in the middle or without tubercles (in females). Apical outer tooth of anterior tibia almost parallel to the internal margin of tibia (Fig. 6) ..... Renorphnus

Acknowledgements

Ilkka Hanski and Heidi Viljanen (UHHF) are acknowledged for providing material for this study and Giulio Cuccodoro (MHNG) for the opportunity to examine the type of Orphnus clementi. Visit of Andrey Frolov to the MNHN was supported by European Distributed Institute of Taxonomy (EDIT).

References

Frolov, A.V., Montreuil, O. 2006. Description of the male of the rare Madagascan species Pseudorphnus hiboni with notes on the genus Pseudorphnus (Coleoptera: Scarabaeidae: Orphninae). Zootaxa, 1154: 27–33.

Paulian R. 1937. Faune entomologique de Madagascar. Coleoptera Lamellicornia, Scarabaeidae Acanthocerini, Trogini, Aulonocnemis, Hybosorini, Orphnini et Ochodaeini. Bulletin de l'Académie malgache (nouvelle série) 19:129-143

Paulian, R. 1977. Les Orphnidae de Madagascar, Insecta, Coleoptera, Scarabaeoidea. Bulletin du Muséum national d'Histoire naturelle de Paris, (3) n 411, Zoologie 288: 1199-1223.

Paulian, R. 1992. Un nouveau genre et une nouvelle espece d'Orphnidae de Madagascar. (Coleopteres, Scarabaeoidea). Revue Française d'Entomologie, (nouvelle série), 14(4): 169-171.

Petrovitz R., 1971. Beitrag zur Kenntnis der Gattung Orphnus M'Leay (Orphninae, Scarabaeidae, Coleoptera). Revue de Zoologie et Botanique Africaine, 84:1-46.