Morphology-based phylogenetic reconstruction of Cholevinae (Coleoptera: Leiodidae): a new view on higher-level relationships

The paralobe: A new diagnostic and synapomorphic character for the genera Paulipalpina Gnaspini & Peck, 1996 and Parapaulipalpina Gnaspini, 1996 (Leiodidae: Cholevinae: Ptomaphagini)

In insect taxa with homogeneous external morphology, genital structures often emerge as essential traits for interspecific differentiation. In the tribe Ptomaphagini (Coleoptera, Leiodidae, Cholevinae), precise identification often depends on analyzing the male genital morphology, even at the genus level. Here, we present a new character for diagnosing the genera Paulipalpina Gnaspini & Peck, 1996 and Parapaulipalpina Gnaspini, 1996. This feature, which we dub 'paralobe', is a projection arising from the internal surface of the right lobe of the aedeagal apex. Based on its absence in other beetles, including other Ptomaphagini, we recognize it as a putative synapomorphy for those genera. The recognition of this previously overlooked structure adds important information for understanding the sequence of changes that occurred in the male genitalia among the genera of Ptomaphagini.

A unique case of commensalism: The beaver beetle Platypsyllus castoris (Leiodidae, Coleoptera) and its morphological adaptations

Platypsyllus castoris is closely associated with beavers and displays a unique set of structural specializations. We document the morphology of adults with modern techniques, and interpret evolutionary changes linked with the specific life style. The small subfamily Platypsyllinae has evolved an entire suite of features correlated with a more or less close association with mammals, for instance a flattened body, a dorsal cephalic shield, flightlessness, eye reduction, and depigmentation. Within this small group, Platypsyllus displays numerous autapomorphic features, correlated with a close association with the beaver. Essential is a combination of mechanical stabilization and firm anchorage on the host, and efficient forward movement in the fur. Exo- and endoskeletal structures of the head and thorax are reinforced by vertical cuticular columns and by an array of internal ridges. The antennae are shortened and strongly modified, the mandibles distinctly reduced and flattened, unsuitable for cutting, scraping or grinding. The musculature of the mouthparts is simplified, whereas an enhanced set of prepharyngeal and pharyngeal dilators forms an efficient sucking pump. The prothoracic musculature is strongly developed. In contrast, the pterothoracic muscle system is distinctly simplified, even though leg muscles are strongly developed. Using the legs, the flattened beetles move sideways through the dense fur of the beaver, using posteriorly directed groups of setae and ctenidia to prevent being pushed backwards by the densely arranged hairs. In contrast to the anterior body, the cuticle of the abdomen is thin, and the entire tagma flexible, with thin layers of segmental muscles. The hind gut is not connected with the mid gut. The beetles probably consume liquid, possibly with emulgated minute skin debris. As the morphology of the mouthparts excludes damage to the skin of the host, the association should not be addressed as ectoparasitic but as commensalism.

A new species of Leonhardia Reitter, 1901 (Coleoptera, Leiodidae, Leptodirini) from Bosnia and Herzegovina, with a key to species of the genus

A new leptodirine leiodid beetle species belonging to the genus Leonhardia Reitter, 1901, L. solakisp. nov., from a pit in Bosnia and Herzegovina (western Balkan Peninsula) is described and diagnosed. Important morphological features of the new species are listed and photographed. The new species is endemic to the Dinarides of Bosnia and Herzegovina. A key for identification of species and subspecies of the genus Leonhardia is also provided.

The ‘twins’ and the ‘bachelor’, new potential synapomorphies inside the Cholevinae (Coleoptera: Leiodidae)

The fine morphology of the tarsus has recently been shown to provide phylogenetic signal at several supraspecific levels in leiodid beetles, as well as in other insects. We here include another system, namely, the spines at the apical margin of the tarsomeres and associated structures. The tribe Ptomaphagini, with a Holarctic-Neotropical-Oriental distribution, has been characterized by having a comb of equal, flat spines around the apex of the tibiae of all legs, with a row of spines extending along the outer edge of the protibia in some genera (which has also been reported in the Eucatopini). We here recognize (as a new synapomorphy for the tribe) that special, strong spines, forming a loose comb, also appear at the apex of the first three or four tarsomeres of the Ptomaphagini. Special features appear on the apical margin of the mesotarsomeres: a long and thin seta, here called the ‘bachelor’, appears between two spines at the external-lateral-ventral face of the first tarsomeres, whereas a group of two (three in some cases) special spines (with the apex bent, facing opposite to each other), here called the ‘twins’, appears on the opposite, internal-lateral-ventral face of the first three (or sometimes two) tarsomeres. We found the ‘twins’ were also present in the Anemadini: Eunemadina and Nemadina, and the Eucatopini; the ‘bachelor seta’ seems to also occur in the Anemadini: Nemadina.

Orogeny, sympatry and emergence of a new genus of Alpine subterranean Trechini (Coleoptera: Carabidae)

Despite two centuries of research in European subterranean habitats, which resulted in descriptions of numerous obligate subterranean beetle species, the role of ecological differentiation in speciation of subterranean beetles remains understudied. Discovery of a new genus and a species of Alpine subterranean Trechini beetles, Petraphaenops unguiculatus gen. & sp. nov., enables us to question the reasons for its morphological and ecological divergence. Multilocus, time-calibrated phylogeny and extensive morphological analyses were used to place the evolution of the species in a temporal and palaeogeographical framework. Set within the phylogeny of Alpine Trechini, the new genus is shown to have split from its sister-genus, Aphaenopidius, by the end of the Pliocene. The timeline of the split between these closely related genera corresponds to the onset of major orogenetic events in the southern Calcareous Alps. The orogeny dynamics, coupled with simultaneous diversification of subterranean habitats, presumably initiated ecological speciation and morphological diversification of this highly troglomorphic subterranean trechine genus.

The thoracic morphology of the troglobiontic cholevine species Troglocharinus ferreri (Coleoptera, Leiodidae)

The thoracic morphology of the troglobiontic leiodid species Troglocharinus ferreri (Cholevinae, Leptodirini) is described and documented in detail. The features are mainly discussed with respect to modifications linked with subterranean habits. Troglocharinus is assigned to the moderately modified pholeuonoid morphotype. The body is elongated and slender compared to epigean leiodids and also cave-dwelling species of Ptomaphagini. The legs are elongated, especially the hindlegs, though to a lesser degree than in the most advanced troglobiontic species. The prothorax is moderately elongated but otherwise largely unmodified. Its muscular system is strongly developed, with more muscle bundles that in free-living staphylinoid or hydrophiloid species. The pterothorax is greatly modified, especially the metathoracic flight apparatus. The meso- and metathoracic elements of the elytral locking device are well-developed, whereas the other notal parts are largely reduced. The mesonotum is simplified, with the triangular scutellar shield as the only distinctly developed part. The mesothoracic musculature is strongly reduced, with only 6 muscles compared to 12 or 13 in free-living staphylinoid or hydrophiloid species. The metanotum is greatly reduced, without a recognizable subdivision into prescutum scutum and scutellum. It is strongly narrowing laterally and lacks notal wing processes and other wing-related elements, but well-developed alacristae are present. The wings are reduced to small membranous flap-like structures inserted at the posterior end of the metanotum. A metapostnotum is not developed. Like in the case of the head, cave dwelling species of the related Ptomaphagini and Leptodirini show different trends of adaptations, with a compact ovoid or navicular body shape in the former, and a distinct trend towards elongation of the body and appendages in the latter tribe. Structural affinities of the thoraces of T. ferreri and the troglobiontic trechine carabid Sinaphaenops wangorum are mainly due to the reduced flight apparatus. The degree of muscle reduction in the pterothorax is very similar in both species.

Ptomaphaginus troglodytes sp. n., the first anophthalmic species of Ptomaphaginina from China (Coleoptera, Leiodidae, Cholevinae, Ptomaphagini)

Ptomaphaginus troglodytessp. n., the first anophthalmic species of Ptomaphaginus Portevin, 1914 is described from two close caves in Libo Karst, south Guizhou Province, China.

Ptomaphaginus troglodytes sp. n., the first anophthalmic species of Ptomaphaginina from China (Coleoptera, Leiodidae, Cholevinae, Ptomaphagini)

Ptomaphaginustroglodytessp. n., the first anophthalmic species ofPtomaphaginusPortevin, 1914 is described from two close caves in Libo Karst, south Guizhou Province, China.