The rare rhinoceros beetle, Ceratophileurus lemoulti Ohaus, 1911, in French Guiana and Suriname (Coleoptera, Scarabaeidae, Dynastinae, Phileurini)

The rare dynastine, Ceratophileurus lemoulti Ohaus, 1911, previously known only from French Guiana, is here reported for the first time from Suriname. All biological, distributional and temporal data available for the species in both territories are presented and discussed.

section_content: Th e tribe Phileurini belongs to the scarab beetle subfamily Dynastinae (commonly called rhinoceros beetles) and contains approximately 225 described species in 36 genera. It is worldwide in distribution. Tropical regions have the most diverse fauna of these beetles, especially in the New World, which has the highest species richness; more than half of all known species occur there (Ratcliff e and Cave 2006). Th e beetles be-longing to this tribe are easily recognised by the enlarged mentum that covers the base of the labial palpi. In the New World, all species are black, fl attened beetles, usually having the elytral striae clearly visible. Th ey are nocturnally active and are attracted to artifi cial light, where they are often collected, although they are also found in decaying trunks and logs, where presumably the majority of species undertake their larval development. Some species have been associated with the nests of termites or ants (Ratcliff e and Cave 2006). Most adult Phileurini do not exhibit distinctive sexual dimorphism or obvious secondary sexual characters as is common in many other Dynastinae, although some do possess horns and other protuberances on the head and/or pronotum. One such species is Ceratophileurus lemoulti Ohaus. 

Th e genus Ceratophileurus contains only the species, C. lemoulti, described from the French overseas Département of Guyane (French Guiana) and which has, until now, been recorded only rarely from that territory. French Guiana has a rich diversity of Dynastinae, with no fewer than 138 species, including 35 species of Phileurini, recorded from there (Ponchel, unpublished data). Th e diversity of Dynastinae in neighbouring Suriname is much less known, with few species recorded in the literature and only about 30 species presently represented in the National Zoological Collections of Suriname (Gillett, personal observation), including four species of Phileurini. French Guiana, Suriname and Guyana (the Guianas) have mostly escaped large-scale human induced alteration of their natural habitats, and consequently still contain vast areas of pristine Amazonian rainforest. 

Ceratophileurus lemoulti is a distinctive species of Phileurini that can be easily identifi ed with the keys of Endrödi (1977 Endrödi (, 1985)). Th e most striking character is the long, recurved and acuminate horn arising from the frons, which is present in both sexes. Th e pronotum of major specimens also bears on each side a short, laterally compressed projection, which is truncate apically (Figs 1-2). It is diffi cult to separate the sexes based on external morphology alone; the only reliable method is to dissect the abdomen to look for the sclerotised parameres found in the male. Th ouvenot (2007) indicated that the only external diff erence between the single male specimen he studied and female specimens was the reduced size of the male. However our data indicate that this is not a reliable character, because female specimens we examined fell within the size range of the few males available for study. Th is paper aims to summarise and consolidate all known biological and distributional data available for C. lemoulti. Suriname. Sipaliwini, Central Suriname Nature Reserve, Raleighvallen, 14-16-II-2000, 1 male (Fig. 2 ), new country record.
section_name: Introduction

section_name: Materials and methods

section_content: Collecting localities for specimens examined are in Fig.
section_name: Specimens

section_content: C. lemoulti is a rare species. Th e holotype was collected by E. Le Moult at St-Laurent-du-Maroni, French Guiana. Since its description, few other records have been published. It appears that the males are particularly scarce in collections; Th ouvenot ( 2007 ) was able to collect only three females in more than 20 years of collecting in French Guiana. Of the 15 specimens we were able to study, only four were males. Whether males are truly less abundant or are less easily attracted to lights remains to be determined. 

Th e possession of well developed horns in box sexes is exceptional within the Scarabaeoidea; usually only the male is armed. Th is condition is also seen in species of Megaphanaeus (Scarabaeinae: Phanaeini), which also exhibit little sexual dimorphism, but in which both sexes possess well developed cephalic and pronotal horns. 

Although the species has been collected during diff erent months, the temporal data indicates a peak activity in May, which represents approximately the onset of the main rainy season in the Guyanas (lasting until August). Many adult Dynastinae are known to be most abundant during the beginning of rainy seasons across the Neotropics (e. g., Ratcliff e 2003; Gillett and Ponchel, personal observations). Equally interesting is the lack of captures during the months of December and January, which approximately coincides with the start of the short rainy season in the Guianas. Th is is a period of known activity for many Coleoptera and it may be signifi cant that it has not been collected during those months. 

As far as is known, all the specimens examined for this paper were collected at artifi cial light (especially mercury vapour light traps) in areas of primary or secondary lowland Amazonian rainforest. Th e species has usually been collected between the hours of 19:00 and 22:00, as is common for many Dynastinae (Ponchel, personal observation). In French Guiana its distribution is scattered, but most localities occur along the north of the territory (Fig. 3 ). However, because access to the remote forested interior of the Département is usually diffi cult, there is a good possibility that this species is also present there. 

No other biological information is available, and the immature stages remain completely unknown. It appears that this species is an endemic and enigmatic element of the fauna of the Guianan shield. Th e single male specimen collected at Raleighvallen in the Central Suriname Nature Reserve is the only specimen recorded to date from Suriname. Raleighvallen is an area of pristine lowland Amazonian rainforest, renowned for its rich biodiversity that remains virtually unknown entomologically. Th is record represents a modest range extension for the species, increasing its distribution by some 250 km to the west of the westernmost locality in French Guiana.
section_name: Discussion

section_name: Acknowledgements

section_content: We express our deep gratitude to Roger-Paul Dechambre (France) and to Guy Silvestre ( France ) for generously sharing their important specimens and data with us. We would like to especially thank Marc and Léticia Stalmans for sharing the results of their collecting in Suriname. We are also indebted to Alain and Marcel Galant ( Belgium ) for the habitus photograph of the specimen, to Paul Schoolmeesters (Belgium) for his continued assistance in locating literature, and to two anonymous reviewers for their constructive comments.
section_name: Acknowledgements