New methods in taxonomy and systematics can influence the overall practice of formally naming and describing biodiversity. DNA barcoding has been controversial since its emergence, but now, large scale species descriptions exclusively based on barcodes have created what can be called a ‘new quality of performance’. Its limitations are discussed from different perspectives: nomenclature, general pragmatism, and problems of DNA-based species delimitation in the light of the central aim of achieving a robust and stable nomenclature of organisms, essential for all applications of biodiversity research. This issue needs to be addressed to prevent restraining the progress of taxonomy and its ability to contribute to modern science.

Results of a phylogenetic analysis of all but one of the 43 recognized extant genera of Ceratocanthinae scarab beetles (Coleoptera: Hybosoridae) are reported. The analysis is based on 97 parsimony informative adult morphological characters scored for 61 ingroup and 10 outgroup terminals. This pantropical subfamily of some 366 species is remarkable for the adults’ ability to pack their body into a tight sub-sphere using interlocking exoskeletal structures (= enrollment coaptations). An overview on known biological and fossil data on the subfamily is provided, as well as a list, an overview, a key and illustrations of adults of all Ceratocanthinae genera. The phylogenetic analysis supports a monophyletic Ceratocanthinae (bootstrap 76%) and a basal dichotomy between pantropical Ceratocanthini (97%) and the South American clade (98%) of Scarabatermitini. Ivieolini renders Scarabatermitini paraphyletic. Another well supported internal clade is the Philharmostes group of seven Afrotropical genera (85%). All other inclusive clades detected in the analysis have low bootstrap support (51–65%), likely indicative of limitations of the adult morphological dataset. We also provide a detailed distribution map of Ceratocanthinae and hypothesize about the South American origin of the subfamily, and that of its two subclades: Ceratocanthini and Scarabatermitini + Ivieolini. Overall this paper summarizes all existing information on Ceratocanthinae beetles in an evolutionary context in order to facilitate and stimulate further research on this subfamily.

Conglobation is an adaptive behaviour occurring independently in various animal groups. Here, we study the evolution of conglobation in Ceratocanthinae, a beetle group with the ability to roll three body segments into a tight ball. It is here implied that this ability evolved only once in the Mesozoic. Evidence is offered suggesting that the high defensive strength of Ceratocanthinae is due not only to the spherical body shape but also to the thickness and stronger mechanical properties of the dorsal cuticle. We further validate five adaptive characters including the allometrically thickened body wall and find that the specific adaptation of different body segments are likely separate evolutionary events. Finally, we propose an “attackers stress” hypothesis to explain the origin of conglobation behaviours. This work contributes to understanding how and why conglobation behaviour may have evolved in this group.

We summarize present day knowledge on Cameroonian Ceratocanthinae and report new findings made during a monthlong collecting trip in 2006. Four forested localities were surveyed: Mt. Oku at 2200–2800 m, Korup National Park at 300 m, Mt. Kupé at 1550 m and Mt. Cameroon at Bakingili village at 250 m. In total we collected 242 specimens representing 14 species, among them nine species new to Cameroon and eight species likely new to science. Four flightless new species are described: Congomostes hintelmanni n. sp., Baloghianestes oribatidiformis n. sp., B. korupensis n. sp. and B. anceps n. sp. Other Ceratocanthinae species presently known from Cameroon are: Baloghianestes lissoubai Paulian, 1968, Callophilharmostes fleutiauxi (Paulian, 1942), Carinophilharmostes vadoni (Paulian, 1937), Melanophilharmostes burgeoni (Paulian, 1946), M. demirei Paulian, 1977, M. zicsii (Paulian, 1968), Philharmostes (Holophilharmostes) badius (Petrovitz, 1967), Petrovitzostes guineensis (Petrovitz, 1968), P. elytratus (Paulian, 1946), P. endroedyi (Paulian, 1974), along with three unnamed species of Melanophilharmostes Paulian, 1968 and one unnamed species of Pseudopterorthochaetes Paulian, 1977. Twelve Cameroonian Ceratocanthinae species are keyed and all 14 recently collected species are illustrated with habitus images.