Cephennodes palpalis, Jaloszynski, 2015

Cephennodes palpalis View in CoL species group

Diagnosis. Conspicuously shortened maxillary palpomere 4, not elongate and strongly narrowing towards truncate apex ( Fig. 124 View FIGURES 124–133 ), but about as long as broad or even slightly transverse and subcylindrical ( Figs 125, 126 View FIGURES 124–133 ); aedeagus of modified simonis form, with elongate drop-shaped capsular region of median lobe, its distal region subtriangular, and apical dorsal plate distally also subtriangular, ventral wall lacking setae; males lacking secondary sexual characters.

This is a newly established species group. The structure of the maxillary palp is relatively stable within all remaining genera of Scydmaeninae , and the difference between the C. palpalis group and all remaining species of Cephennodes could justify a separate status of these three species, even in a separate genus. The maxillary palpomere 4 in all remaining species of Cephennodes is elongate, as in Fig. 124 View FIGURES 124–133 , and it seems to strongly differ from that in Figs 125 and 126 View FIGURES 124–133 . However, all remaining groundplan morphological characters of the new group are identical to those in all other Cephennodes spp. , and also the maxillary palpomere 4 even within the palpalis group is clearly variable in width and length in relation to the penultimate segment. It seems that this modification, restricted to a closely related three species (judging from their very similar aedeagi) is rather a transformation that has evolved within the Cephennodes clade, and not even within its most basal branches. This conclusion is made based on the fact that in all remaining genera of Cephenniini the aedeagus is symmetrical, except for Hlavaciellus , a sister group of Cephennodes ( Jałoszyński 2011b; a, 2012a, 2018), and also the symmetrical form is preserved in some groups of species within Cephennodes . Therefore, the asymmetry, as that in the C. palpalis group, is a derived condition. The ancestor of Cephennodes and Hlavaciellus had a symmetrical aedeagus. For this reason, a group of species with a strongly asymmetrical aedeagus and a transformed maxillary palpomere 4 is very unlikely a sister group of all remaining Cephennodes species.

This is a small group that includes the Chinese C. palpalis Jałoszyński, 2015c and two newly described species.

Key to males of Cephennodes palpalis View in CoL species group

1 Elytra with setae arranged in conspicuous pattern, in lateral (outer) region near posterior third directed laterad, and in inner (mesal) region directed caudad; apical region of basal capsule of median lobe in ventral view narrowly subtriangular and pointed, with lateral margins concave................................................. C. pseudopalpalis sp. nov.

- Elytra with ‘regular’ setae, not arranged in conspicuous pattern; apical region of basal capsule of median lobe in ventral view either subtriangular and blunt with lateral margins nearly straight, or extremely long and elongate, forming rod-like projection........................................................................................... 2

2 Body strongly elongate, (PL+EL)/EW about 1.9; apical region of median lobe in ventral view subtriangular............................................................................................... C. palpalis Jałoszyński View in CoL

- Body stout, (PL+EL)/EW about 1.6; apical region of median lobe in ventral view extremely long, forming rod-like projection.............................................................................. C. mirus View in CoL sp. nov.