Diarthroconnus Ganglbauer, 1900

Jałoszyński, Paweł, 2017, Taxonomy of ' Euconnus complex'. Part XIV. Diarthroconnus is removed from synonymy with Psomophus and placed as a junior synonym of Euconnus s. str. (Coleoptera, Staphylinidae, Scydmaeninae), Zootaxa 4317 (1), pp. 191-195 : 192

Morphological structures and taxonomic status of Diarthroconnus Ganglbauer

The syntype females of Euconnus (Diarthroconnus) birnbacheri (the one designated as lectotype is shown in Fig. 1 ) do not show any diagnostic characters of Psomophus (= Spanioconnus ; discussed in Jałoszyński (2017c)), and they are not conspecific with Euconnus (Psomophus) intrusus . Apart from clearly teratological antennae ( Figs 1 , 6 ), E. birnbacheri is identical with the broadly distributed (known also to occur in Austria) Euconnus (s. str.) fimetarius ( Chaudoir, 1845) ( Fig. 2 ). It shows the same body shape, size and proportions of body parts as females of E. fimetarius from Central Europe used for comparative study; no differences were also found in any fine structures ( Figs 3–6 ).

The antennae of E. birnbacheri ( Fig. 5 ) are unusual and certainly teratological. The antennomeres I–VII seem normally developed, but the distal ones are fused and forming two large compound antennomeres. Such cases of teratology were already known in Euconnus ( Reitter 1900; Horion 1949), and I have seen specimens of Euconnus (Tetramelus) with a very similar condition. Another specimen of Euconnus fimetarius with similarly aberrant antennae was also found in NHMW (see Remarks below). In Euconnus s. str., antennae ( Fig. 2 ) are slender and gradually thickened distally; the antennomeres I–VII in the female of E. fimetarius shown in Fig. 2 have similar proportions as those in E. birnbacheri .

Conclusions. Euconnus birnbacheri is not conspecific with E. intrusus and does not belong to the same subgenus. The type series of this species is composed of teratological females of Euconnus (s. str.) fimetarius . Consequently, Diarthroconnus is removed from synonymy with Psomophus and placed as a junior synonym of Euconnus (s. str.).

Lectotype designation. Ganglbauer (1900) clearly mentioned two specimens. Of these two female syntypes the one illustrated in Fig. 1 and labeled as in Fig. 7 is here designated lectotype.

Remarks. The third teratological female of E. fimetarius mentioned above was found in NHMW among Ganglbauer's specimens, and it was labeled as birnbacheri presumably by Ganglbauer himself, judging from a very similar handwriting. However, Ganglbauer (1900) mentioned only two specimens included in the type series, both collected in Villach and received from Birnbacher; this information agrees with the label data ( Fig. 7 ). The third female was collected in an unspecified locality in Austria by Winkler; it does not belong to the type series of E. birnbacheri .

Figures

FIGURES 1 – 2. Dorsal habitus of Euconnus (Diarthroconnus) birnbacheri Ganglbauer, female lectotype (Austria) (1) and Euconnus (s. str.) fimetarius (Chaudoir), female (Poland) (2).

FIGURES 5 – 7. Morphological structures of Euconnus (Diarthroconnus) birnbacheri Ganglbauer, female lectotype (5 – 6) and original set of labels of lectotype (7). Left antenna in dorsal view (5); pterothorax in ventral view (6). Abbreviations: pcr, procoxal rest; msvp, mesoventral intercoxal process; mtvp, metaventral intercoxal process.

FIGURES 3 – 4. Morphological structures of Euconnus (Diarthroconnus) birnbacheri Ganglbauer, female lectotype. Head, prothorax and elytral base in dorsal view (3); head, prothorax and anterior portion of mesothorax in ventral view (4). Abbreviations: abp, antebasal pit; bef, basal elytral fovea; bst, basisternal part of prosternum; fr, frons; gp, gular plate; hr, hypostomal ridge; hyr, hypomeral ridge; mn, mentum; nss, notosternal suture; ptp, posterior tentorial pit; slc, sublateral carina; smn, submentum; vt, vertex.