Wednesday, February 20, 2013

[Entomology • 2013] A systematic revision of Operclipygus Marseul (Coleoptera, Histeridae, Exosternini)


Figure 13. Operclipygus conquisitus group.
A Dorsal habitus of Operclipygus conquisitus B Dorsal habitus of Operclipygus bicolor
C Metaventrite of Operclipygus bicolor D Dorsal habitus of Operclipygus friburgius
E Ventral habitus of Operclipygus friburgius

Little did we know about beetle diversity: Astonishing 138 new species in a single genus

The tropics are home to an extraordinary diversity of insect species. How great is it, exactly? We do not know, but today, researchers at the Santa Barbara Museum of Natural History published a study on tropical beetles that can help us progress towards an answer to this question. The paper was published in the open access, peer-reviewed journal Zookeys [doi: 10.3897/zookeys.271.4062].

Entomologists Michael Caterino and Alexey Tishechkin have named 138 new species within the genus Operclipygus (the name refers to their clamshell-like rear end), thereby increasing the size of the genus over six times. The work is based on a study of over 4000 specimens amassed from natural history museums all over the World, as well as specimens from fieldwork collected throughout Central and South America by the authors.

The lead co-author of the paper, Dr. Caterino, comments of on the significance of such biodiversity: 'We all know that forests in the tropics are disappearing. But we only have the faintest idea of how much biodiversity is disappearing with them. Studies like this are critical to seeing where the greatest diversity is, and finding out the best ways to protect it',

These beetles all belong to a family known as histerids, or 'clown beetles'. All of the newly described species are similar in appearance to a poppy seed – small, round and black. Because of their extreme abundance, however, they have an ecological importance disproportionate to their size. As voracious predators of other insects' larvae, these beetles help controlling pestiferous flies. As in some cases their menu includes fly larvae found in decomposing bodies, some researchers have been promoting their use in forensic investigations.

Since the days of Darwin, Wallace, and Bates, entomologists have both celebrated and bemoaned the overwhelming diversity of tropical insects. Modern-day scientists continue to grapple with the question of just what extent of insect biodiversity lives in the tropical parts of the World, with estimates ranging from 5 to 30 million species or more. This study is only one part of a larger revision of several related histerid genera, and it seems not to be an isolated case, with most groups revealing 5 to 6 times the species currently documented.

So while biologists have a long way to go in fully documenting the species diversity in rapidly-disappearing tropical forests, comprehensive taxonomic revisions of neglected insect groups can help to clarify the magnitude of what's at stake. This project was funded by the Advancing Revisionary Taxonomy and Systematics program of the U.S. National Science Foundation, and it clearly demonstrates what dedicated support for taxonomy can do for our understanding of global biodiversity.

Dr. Caterino closes: 'We're committed to doing our best to let people know what's out there before it's too late'.


Little did we know about beetle diversity: Astonishing 138 new species in a single genus

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Abstract
We revise the large Neotropical genus Operclipygus Marseul, in the histerid tribe Exosternini (Histeridae: Histerinae). We synonymize 3 species, move 14 species from other genera, sink the genus Tribalister Horn into Operclipygus, and describe 138 species as new, bringing the total to 177 species of Operclipygus. Keys are provided for the identification of all species, and the majority of the species are illustrated by habitus and male genitalia illustrations. The species are diverse throughout tropical South and Central America, with only a few species extending into the temperate parts of North America. The majority of species can be recognized by the presence of a distinct stria or sulcus along the apical margin of the pygidium, though it is not exclusive to the genus. Natural history details for species of Operclipygus are scant, as most specimens have been collected through the use of passive flight interception traps. Many are probably generally associated with decaying vegetation and leaf litter, where they prey on small arthropods. But a small proportion are known inquilines, with social insects such as ants and termites, and also with some burrowing mammals, such as Ctenomys Blainville. 

The genus now includes the following species groups and species: 
Operclipygus sulcistrius group [Operclipygus lucanoides sp. n., Operclipygus schmidti sp. n., Operclipygus simplistrius sp. n., Operclipygus sulcistrius Marseul, 1870], 
Operclipygus mirabilis group [Operclipygus mirabilis (Wenzel & Dybas, 1941) comb. n., Operclipygus pustulifer sp. n., Operclipygus plaumanni sp. n., Operclipygus sinuatus sp. n., Operclipygus mutuca sp. n., Operclipygus carinistrius (Lewis, 1908) comb. n., Operclipygus parensis sp. n., Operclipygus schlingeri sp. n.], 
Operclipygus kerga group [Operclipygus kerga (Marseul, 1870), Operclipygus planifrons sp. n., Operclipygus punctistrius sp. n.], 
Operclipygus conquisitus group [Operclipygus bicolor sp. n., Operclipygus conquisitus (Lewis, 1902), Operclipygus friburgius (Marseul, 1864)], 
Operclipygus impuncticollis group [Operclipygus bickhardti sp. n., Operclipygus britannicus sp. n., Operclipygus impuncticollis (Hinton, 1935)], 
Operclipygus panamensis group [Operclipygus crenatus (Lewis, 1888), Operclipygus panamensis (Wenzel & Dybas, 1941)], 
Operclipygus sejunctus group [Operclipygus depressus (Hinton, 1935), Operclipygus itoupe sp. n., Operclipygus juninensis sp. n., Operclipygus pecki sp. n., Operclipygus punctiventer sp. n., Operclipygus sejunctus (Schmidt, 1896) comb. n., Operclipygus setiventris sp. n.], 
Operclipygus mortavis group [Operclipygus ecitonis sp. n., Operclipygus mortavis sp. n., Operclipygus paraguensis sp. n.], 
Operclipygus dytiscoides group [Operclipygus carinisternus sp. n., Operclipygus crenulatus sp. n., Operclipygus dytiscoides sp. n., Operclipygus quadratus sp. n.], 
Operclipygus dubitabilis group [Operclipygus dubitabilis (Marseul, 1889), Operclipygus yasuni sp. n.], 
Operclipygus angulifer group [Operclipygus angulifer sp. n., Operclipygus impressifrons sp. n.], 
Operclipygus dubius group [Operclipygus andinus sp. n., Operclipygus dubius (Lewis, 1888), Operclipygus extraneus sp. n., Operclipygus intermissus sp. n., Operclipygus lunulus sp. n., Operclipygus occultus sp. n., Operclipygus perplexus sp. n., Operclipygus remotus sp. n., Operclipygus validus sp. n., Operclipygus variabilis sp. n.], 
Operclipygus hospes group [Operclipygus assimilis sp. n., Operclipygus belemensis sp. n., Operclipygus bulbistoma sp. n., Operclipygus callifrons sp. n., Operclipygus colombicus sp. n., Operclipygus communis sp. n., Operclipygus confertus sp. n., Operclipygus confluens sp. n., Operclipygus curtistrius sp. n., Operclipygus diffluens sp. n., Operclipygus fusistrius sp. n., Operclipygus gratus sp. n., Operclipygus hospes (Lewis, 1902), Operclipygus ibiscus sp. n., Operclipygus ignifer sp. n., Operclipygus impositus sp. n., Operclipygus incisus sp. n., Operclipygus innocuus sp. n., Operclipygus inquilinus sp. n., Operclipygus minutus sp. n., Operclipygus novateutoniae sp. n., Operclipygus praecinctus sp. n., Operclipygus prominens sp. n., Operclipygus rileyi sp. n., Operclipygus subterraneus sp. n., Operclipygus tenuis sp. n., Operclipygus tiputinus sp. n.], 
Operclipygus farctus group [Operclipygus atlanticus sp. n., Operclipygus bidessois (Marseul, 1889), Operclipygus distinctus (Hinton, 1935), Operclipygus distractus (Schmidt, 1896) comb. n., Operclipygus farctissimus sp. n., Operclipygus farctus (Marseul, 1864), Operclipygus gilli sp. n., Operclipygus impressistrius sp. n., Operclipygus inflatus sp. n., Operclipygus latemarginatus (Bickhardt, 1920) comb. n., Operclipygus petrovi sp. n., Operclipygus plicatus (Hinton, 1935) comb. n., Operclipygus prolixus sp. n., Operclipygus punctifrons sp. n., Operclipygus proximus sp. n., Operclipygus subrufus sp. n.], 
Operclipygus hirsutipes group [Operclipygus guianensis sp. n., Operclipygus hirsutipes sp. n.], 
Operclipygus hamistrius group [Operclipygus arquus sp. n., Operclipygus campbelli sp. n., Operclipygus chiapensis sp. n., Operclipygus dybasi sp. n., Operclipygus geometricus (Casey, 1893) comb. n., Operclipygus hamistrius (Schmidt, 1893) comb. n., Operclipygus impressicollis sp. n., Operclipygus intersectus sp. n., Operclipygus montanus sp. n., Operclipygus nubosus sp. n., Operclipygus pichinchensis sp. n., Operclipygus propinquus sp. n., Operclipygus quinquestriatus sp. n., Operclipygus rubidus (Hinton, 1935) comb. n., Operclipygus rufescens sp. n., Operclipygus troglodytes sp. n.], 
Operclipygus plicicollis group [Operclipygus cephalicus sp. n., Operclipygus longidens sp. n., Operclipygus plicicollis (Schmidt, 1893)], 
Operclipygus fossipygus group [Operclipygus disconnectus sp. n., Operclipygus fossipygus (Wenzel, 1944), Operclipygus foveipygus (Bickhardt, 1918), Operclipygus fungicolus (Wenzel & Dybas, 1941), Operclipygus gibbulus (Schmidt, 1889) comb. n., Operclipygus olivensis sp. n., Operclipygus simplicipygus sp. n., Operclipygus subdepressus (Schmidt, 1889), Operclipygus therondi (Wenzel, 1976)], 
Operclipygus impunctipennis group [Operclipygus chamelensis sp. n., Operclipygus foveiventris sp. n., Operclipygus granulipectus sp. n., Operclipygus impunctipennis (Hinton, 1935) comb. n., Operclipygus latifoveatus sp. n., Operclipygus lissipygus sp. n., Operclipygus maesi sp. n., Operclipygus mangiferus sp. n., Operclipygus marginipennis sp. n., Operclipygus nicodemus sp. n., Operclipygus nitidus sp. n., Operclipygus pacificus sp. n., Operclipygus pauperculus sp. n., Operclipygus punctissipygus sp. n., Operclipygus subviridis sp. n., Operclipygus tripartitus sp. n., Operclipygus vorax sp. n.], 
Operclipygus marginellus group [Operclipygus ashei sp. n., Operclipygus baylessae sp. n., Operclipygus dentatus sp. n., Operclipygus formicatus sp. n., Operclipygus hintoni sp. n., Operclipygus marginellus (J.E. LeConte, 1860) comb. n., Operclipygus orchidophilus sp. n., Operclipygus selvorum sp. n., Operclipygus striatellus (Fall, 1917) comb. n.], incertae sedis: O. teapensis (Marseul, 1853) comb. n., Operclipygus punctulatus sp. n., Operclipygus lama Mazur, 1988, Operclipygus florifaunensis sp. n., Operclipygus bosquesecus sp. n., Operclipygus arnaudi Dégallier, 1982, Operclipygus subsphaericus sp. n., Operclipygus latipygus sp. n., Operclipygus elongatus sp. n., Operclipygus rupicolus sp. n., Operclipygus punctipleurus sp. n., Operclipygus falini sp. n., Operclipygus peregrinus sp. n., Operclipygus brooksi sp. n., Operclipygus profundipygus sp. n., Operclipygus punctatissimus sp. n., Operclipygus cavisternus sp. n., Operclipygus siluriformis sp. n., Operclipygus parallelus sp. n., Operclipygus abbreviatus sp. n., Operclipygus pygidialis (Lewis, 1908), Operclipygus faltistrius sp. n., Operclipygus limonensis sp. n., Operclipygus wenzeli sp. n., Operclipygus iheringi (Bickhardt, 1917), Operclipygus angustisternus (Wenzel, 1944), Operclipygus shorti sp. n. 

We establish the following synonymies: Phelisteroides miladae Wenzel & Dybas, 1941 and Pseudister propygidialis Hinton, 1935e = Operclipygus crenatus (Lewis, 1888); Phelister subplicatus Schmidt, 1893b = Operclipygus bidessois (Marseul, 1889). We designate lectotypes for Operclipygus sulcistrius Marseul, 1870, Phelister carinistrius Lewis, 1908, Phelister kerga Marseul, 1870, Phelister friburgius Marseul, 1864, Phelister impuncticollis Hinton, 1935, Phelister crenatus Lewis, 1888, Phelister sejunctus Schmidt, 1896, Pseudister depressus Hinton, 1935, Epierus dubius Lewis, 1888, Phelister hospes Lewis, 1902, Phelister farctus Marseul, 1864, Phelister bidessois Marseul, 1889, Phelister subplicatus Schmidt, 1893, Phelister plicatus Hinton, 1935, Phelister distinctus Hinton, 1935, Phelister distractus Schmidt, 1896, Pseudister latemarginatus Bickhardt, 1920, Phelister hamistrius Schmidt, 1893, Phelister plicicollis Schmidt, 1893, Phelister gibbulus Schmidt, 1889, Phelister subdepressus Schmidt, 1889, Phelister teapensis Marseul, 1853, Phelister pygidialis Lewis, 1908, Phelister iheringi Bickhardt, 1917, and Phelister marginellus J.E. LeConte 1860. We designate a neotype for Operclipygus conquisitus Lewis, replacing its lost type specimen.

Keywords: Histeridae, Histerinae, Exosternini, Operclipygus, myrmecophily, Neotropical region


Caterino, M.S., Tishechkin, A.K. 2013. A systematic revision of Operclipygus Marseul (Coleoptera, Histeridae, Exosternini). ZooKeys. 271: 1–401. doi: 10.3897/zookeys.271.4062

Little did we know about beetle diversity: Astonishing 138 new species in a single genus

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