Catalogue, distribution, taxonomic notes, and conservation of the Western Palearctic endemic hunchback beetles (Tenebrionidae, Misolampus)

Abstract

Hunchback darkling beetles of the Ibero-Maghrebian genus Misolampus Latreille, 1807 (Tenebrionidae, Stenochiinae) encompass six species: M. gibbulus (Herbst, 1799), M. goudotii Guérin-Méneville, 1834, M. lusitanicus Brême, 1842, M. ramburii Brême, 1842, M. scabricollis Graells, 1849, and M. subglaber Rosenhauer, 1856. Previously known distribution ranges of the species were delineated using many old records, the persistence of such populations being questionable under the current situation of global biodiversity loss. Additionally, the status of geographically isolated populations of the genus have been the subject of taxonomic controversy. An exhaustive bibliographical revision and field search was undertaken, and the Misolampus collection of the Museo Nacional de Ciencias Naturales (MNCN-CSIC) was revised. The aims are to (i) provide an updated geographic distribution range for the species of Misolampus; (ii) to determine the taxonomic status of controversial populations; (iii) to provide a catalogue for Misolampus; and (iv) to discuss the conservation status of these saproxylic beetles. As a result, a catalogue including synonymies and type localities, geographical records, diagnoses, and information on natural history for all species of Misolampus is presented. The results reveal that the distribution ranges of the species of Misolampus have not undergone a reduction in the last century, and indicate the presence of the genus in areas where it had never been recorded before. The morphological variability of M. goudotii drove the proposal of different taxa that are here formally synonymised as follows: M. goudotii Guérin-Méneville, 1834 = M. erichsoni Vauloger de Beaupré, 1900, syn. nov. = M. peyerimhoffi Antoine, 1926, syn. nov.

Geology‐based and ecological processes of divergence between and within species of wingless darkling beetles

“…The four selected bioclimatic variables for the ancestral state estimations showed a strong phylogenetic signal, particularly marked in the case of precipitation of driest quarter (BIO17) and mean temperature of wettest quarter (BIO8, Figure 4; Table 1). The recent history of isolation across populations with obvious patterns of morphological differentiation within M. gibbulus and M. goudotii (Rosas‐Ramos et al, 2020) were confirmed by our analyses. These species, characterized by high levels of intraspecific diversity, are distributed in the southwest of the Iberian Peninsula and in Morocco, regions previously identified as climatic refugia across a variety of taxa (Abellán & Svenning, 2014; Gutiérrez‐Rodríguez et al, 2017; Martínez‐Freiría et al, 2020; Miraldo et al, 2011; Sánchez‐Montes et al, 2019).…”

“…Indeed, the north‐east of the peninsula would have been dominated by herbaceous vegetation, with small‐isolated areas within the regional steppic feature with local riparian forest (Jiménez‐Moreno et al, 2010). These past conditions and vegetation composition, together with the formation of the Ebro and Tagus Basins, provide clues for the current absence of Misolampus in the region, yet with favourable areas like Iberian Chain (Rosas‐Ramos et al, 2020). The southern area of the Iberian Peninsula was also characterized by herbaceous vegetation, even subdesertic flora implying dry and warm conditions, where mesothermic trees were probably in mid‐or high altitudes.…”

“…We inferred climatically suitable areas for all Misolampus species under current and past climatic conditions using species distribution models (SDMs). Based on current occurrence data of Misolampus (Rosas‐Ramos et al, 2020), we built SDMs with a total of 509 presence records (56 of M. subglaber , 133 of M. scabricollis , 30 of M ramburii , 13 of M. lusitanicus , 137 of M. goudotii , and 140 of M. gibbulus ). The 19 bioclimatic variables available in the WorldClim 2.0 dataset (Fick & Hijmans, 2017) were used as predictor variables to build models of environmental suitability under current and past climate conditions.…”

“…On the other hand, Misolampus could be of recent origin (Pliocene), with less time to experience geological events, and diversification could be then largely attributed to dispersal events from their ancestral area to other areas (Figure 1b). This scenario might be facilitated by the broad climatic tolerance of Misolampus , which are also associated with tree species that are widespread throughout the Mediterranean Basin (Rosas‐Ramos et al, 2020). Finally, while it has been previously proposed that the ancestor of Misolampus originated in North Africa and subsequently dispersed towards the Iberian Peninsula (Palmer, 1998; Palmer & Cambefort, 2000), an alternative scenario could invoke an intermediate origin (Miocene) and a dual role of vicariance and dispersal in driving the biogeographical pattern observed today (Figure 1c).…”

Proctodeal extrusion as a defensive behavioral response in blister beetles (Coleoptera: Meloidae)

“…During a series of field surveys conducted with the aim of analyzing the systematic position and conservation status of some species of Tenebrionoidea (López-Estrada et al 2019;Rosas-Ramos et al 2020), we observed a peculiar behavior in the endemic Iberian species Physomeloe corallifer (Germar, 1818). When handled, specimens of this taxon consistently extruded inner abdominal membranes from the proctodeal region (proctodeum: the embryonic posterior ectodermal part of the digestive tract, Merriam-Webster 2020; for a histological description of this region in a blister beetle, see Senarat et al 2014), which appeared intensely red or orange colored when the hemolymph is seen through them.…”