''Phoberus disjunctus'' is a species of

hide beetle Trogidae, sometimes called hide beetles, is a family of beetles with a distinctive warty or bumpy appearance. Found worldwide, the family includes about 300 species contained in four or five genera. Trogids range in length from 2 to 20 mm. Thei ...

in the subfamily

Troginae ''Troginae'' is a subfamily of beetles in the family Trogidae which includes extant species and extinct beetle species from the Lower Cretaceous. The subfamily contains the following genera: * Glyptotrox Nikolajev, 2016 *Paratrox ''Paratrox ...

discovered by coleopterologist Werner P. Strümpher in 2016.

Taxonomy

Initially, the scientific community treated all ''P. disjunctus'' specimens as part of the ''P. capensis'' species. These beetle specimen resided within the genus ''Trox''. When ''Phoberus'' was recognized as a full genus, taxonomists moved ''P. capensis'', and all ''P. disjunctus'' beetles along with it, from the genus ''Trox'' to the genus ''Phoberus''. Recent evolutionary genetics allowed coleopterologist Strümpher and his team to uncover molecular and morphological differences between mainline ''P. capensis'' beetles and the ''P. disjunctus'' variant, causing the new ''Phoberus disjunctus'' species to be discovered and classified. Within the genus ''Phoberus'', ''P. disjunctus'' is most similar to ''P. capensis'' and ''P. herminae'' due to their shared evolutionary history, and historically researchers have often confused the three species for each other. ''P. disjunctus'' can be distinguished from the other two hide beetles by the shape of their pronota. Specifically, ''P. disjunctus'' has an evenly-rounded disc on the pronotum with a shallow depression running through its middle; by contrast, ''P. capensis'' and ''P. herminae'' have a high disc on the pronotum, whose margins spike out from the beetle's carapace, and a deep valley-like depression runs through their disc's middle.

Morphology

''Phoberus disjunctus'' is between 5 and 6 millimeters long and 3 and 4 millimeters wide. The hide beetle species has long

paramere Parameres ('side parts') are part of the external reproductive organs of male insects and the term was first used by Karl Wilhelm Verhoeff, Verhoeff in 1893 for the lateral genital lobes in Coleoptera. The primary phallic lobes which appear in th ...

s that are about two-thirds as long as their penis-like

aedeagus An aedeagus ( or aedeagi) is a reproductive organ of male arthropods through which they secrete sperm from the testes during copulation (zoology), copulation with a female. It can be thought of as the insect equivalent of a mammal's penis, th ...

Distribution and diet

''P. disjunctus'' lives within the

South Africa South Africa, officially the Republic of South Africa (RSA), is the Southern Africa, southernmost country in Africa. Its Provinces of South Africa, nine provinces are bounded to the south by of coastline that stretches along the Atlantic O ...

n province of

Western Cape The Western Cape ( ; , ) is a provinces of South Africa, province of South Africa, situated on the south-western coast of the country. It is the List of South African provinces by area, fourth largest of the nine provinces with an area of , an ...

. Specifically, its geographical distribution follows the

Cape Fold Mountains The Cape Fold Belt (CFB) is a long fold-and-thrust mountain belt along the western and southern coastlines of Western Cape, South Africa. The Cape Fold Belt formed during the Permian period (300 to 250million years ago) in the late Paleozoic ...

, a pattern of range seen across many beetle groups in South Africa. However, ''P. disjunctus'' survives best in mountainous ecosystems at high altitudes, and so its range is extremely scattered into a series of population islands along the

Swartberg The Swartberg mountains (''black mountain'' in English language, English) are a mountain range in the Western Cape province of South Africa. It is composed of two main mountain chains running roughly east–west along the northern edge of the sem ...

Matroosberg Matroosberg (Afrikaans for 'Sailor Mountain') is a peak in the South African Hex River Mountains, which belong to the Cape Fold Belt. With a height of above sea level, it is the highest mountain in the Cape Winelands District Municipality. The ...

, and

Cederberg The Cederberg mountains are located near Clanwilliam, Western Cape, Clanwilliam, approximately 300 km north of Cape Town, South Africa at about . The mountain range is named after the endangered Clanwilliam cedar (''Widdringtonia cedarbe ...

Mountains. This ground-based beetle is a detritivore and survives by consuming keratin from animal feces and rotting meat.

Evolutionary history

''P. disjunctus'', along with ''P. capensis'' and ''P. herminae'', form the "capensis" node of the genus ''Phoberus''. The three species all came from ''Phoberus capensis''. At least four million years ago, ''P. capensis'' diverged from its closest relative outside the capensis node, ''P. nasutus''. Then, sometime in the Pliocene or early Pleistocene, ''P. capensis'' diversified, with fragment populations splitting off and evolving into two new species. Rapid climate changes leading up to the ice ages likely prompted this evolution, as they affected hide beetle populations unequally. In most South African ecosystems, ''P. capensis'' populations plummeted. However, the Cape Fold Mountains contain a patchwork of forests, coastal plains, and mountain summits that are relatively cold, temperate, and much more stable than the surrounding ecosystems, serving as a buffer that shielded ''P. capensis'' populations within them. In the mountains, the ancestors of ''P. disjunctus'' were isolated from ''P. capensis'' groups that had taken refuge in other patchwork biomes, leading to allopatric speciation (evolution from geographic separation).

References

{{Taxonbar, from=Q86603348 Phoberus, disjunctus Beetles described in 2016