Palaeoleptochromus O'Keefe

Paweł Jałoszyński, 2018, World genera of Mastigitae: review of morphological structures and new ecological data (Coleoptera: Staphylinidae: Scydmaeninae), Zootaxa 4453 (1), pp. 1-119 : 50

† Palaeoleptochromus O'Keefe

Palaeoleptochromus O'Keefe, 1997: 380 (in O’Keefe et al. (1997)). Type species: Palaeoleptochromus schaufussi O'Keefe, 1997 (orig. des.).

Palaeoleptochromus , with its sole species P. schaufussi ( Fig. 86 ) from the Upper Cretaceous Canadian amber, differs from Clidicus in a pair of long setae on the posterior margin of vertex and the labial palps: the palpomere II is pedunculate and strongly broadened in its distal half, where it is about 4 times as broad as at base, and palpomere III is bristle-like, extremely slender and pointed. Other characters included in the original description seem to agree with those of Clidicus , except that P. schaufussi is very small, only 2.23 mm long (although the smallest Clidicus is 2.99 mm long). The type specimen was not available for my study, but it seems that most characters crucial to place P. schaufussi in a taxonomic context are not observable in the inclusion. In the recently published phylogenetic analysis Palaeoleptochromus was placed within Clidicus , and these names may be synonymous, but the evidence for this is too scarce to make such a decision. The placement of Palaeoleptochromus remains unclear.

Figures

FIGURES 86–88. Clidicini, examples of extinct species; lateral (86), ventral (87) and lateroventral (88) habitus. Palaeoleptochromus schaufussi (86; Upper Cretaceous of Canada; photo Brendon Strilisky); Clidicus archaicus (87; Upper Cretaceous of Myanmar); Clidicus sp. (88; Upper Eocene of Europe).