Euconnus

Jałoszyński, Paweł, 2016, Taxonomy of ' Euconnus complex'. Part VIII. Subgenera Napoconnus, Himaloconnus and Nepaloconnus removed from Euconnus (Coleoptera, Staphylinidae, Scydmaeninae), Zootaxa 4103 (5), pp. 463-472 : 464-467

1. Morphological structures and taxonomic status of Euconnus ( Napoconnus Franz )

The general body shape of Euconnus (Napoconnus) kubienai ( Fig. 1 ) is very similar to that of many species of Euconnus , especially the subgenus Napochus .

The head capsule ( Figs 1 , 10 ) is divided into the posterior part ('neck' region) and anterior, exposed part by an occipital constriction broader than half width of head. The anterior part of the head is slightly elongate and distinctly flattened; vertex distinctly demarcated from the 'neck' region and not bulging posterodorsally; frons subtrapezoidal; antennal insertions moderately broadly separated; compound eyes located anterolaterally, so that the tempora are long. The tempora and genae are covered with thick bristles ( Fig. 10 ). The posterior tentorial pits ( Fig. 10 ; ptp) are elongate and located slightly in front of the transverse impression demarcating ventrally the anterior and posterior parts of the head capsule; the gular plate ( Fig. 10 ; gp) is broad and subtrapezoidal, but with its anterior portion adjacent to the tentorial pits narrowed and elongate. The submentum ( Fig. 10 ; smn) is not demarcated laterally by sutures, and hypostomal ridges ( Fig. 10 ; hr) are short, strongly bent mesally and running nearly parallel to the posterior margins of cardines. Most of these characters can be found in Euconnus , except for the unusually short and strongly bent mesally hypostomal ridges (in Euconnus s. str., Napochus , Filonapochus , Tetramelus , Paratetramelus , Heteroconnus and Glabriconnus the ridges are long and extend posteromesally nearly to the posterior tentorial pits; in Rhomboconnus the posterior ends of ridges are far from tentorial pits but connected at middle).

The antennae ( Figs 1 , 11 ) of Euconnus (Napoconnus) kubienai are relatively short, with scape and pedicel elongate and proximal flagellomeres subcylindrical and compactly assembled; the club is composed of three antennomeres, of which the antennomere IX is only slightly broader than VIII and therefore the club appears as two-segmented. Antennomeres X and XI are much broader and longer than IX. Such composition of the antennal club is not known in any of the hitherto reviewed subgenera of Euconnus , but in other species of Napoconnus (e.g., Franz 1957) the club is clearly three-segmented, with the antennomere IX about as broad as X and XI. Antennal clubs in such species resemble those of Napochus , except for being three-, and not four-segmented.

The prothorax of Euconnus (Napoconnus) kubienai in dorsal view ( Fig. 1 ) is elongate and subtrapezoidal, with sides nearly straight and strongly convergent anteriorly, the pronotum is broadest near base. The pronotal base bears a faint transverse impression and a pair of feebly marked lateral antebasal pits. The general shape of pronotum is very similar to that of Napochus .

The prosternum ( Fig. 10 ) is short, lacking prosternal process or carina; the notosternal sutures ( Fig. 10 ; nss) and hypomeral ridges ( Fig. 10 ; hyr) seem complete (but they are only partly visible in the studied specimen), and the sides of prothorax are covered with thick bristles. These are characters similar to those known in Napochus .

The mesoventral structures, especially the carinate, narrow and highly elevated mesoventral intercoxal process ( Fig. 12 ; msvp) of Euconnus (Napoconnus) kubienai do not deviate from those known in Euconnus s. str. and other subgenera of Euconnus .

The metaventral intercoxal process of Euconnus (Napoconnus) kubienai ( Fig. 12 ; mtvp) is not similar to structures found in previously studied subgenera of Euconnus . Instead of being moderately broad and short, as in Euconnus , the process in Napoconnus is narrow and forming a pair of long spines touching at middle and projecting posteriorly, so that the metacoxae are narrowly separated.

The elytra ( Fig. 1 ) are oval, elongate, each with two barely noticeable asetose rudiments of basal foveae. This character differs from conditions known in most subgenera of Euconnus , which have large and deep basal elytral foveae. However, the foveae are either entirely reduced or visible only as barely discernible rudiments in Rhomboconnus and Filonapochus , or they can be very small ( Heteroconnus and some species of Napochus ).

The aedeagus ( Figs 2–3 ) of Euconnus (Napoconnus) kubienai is symmetrical, with free and slender parameres, sub-basally located dorsal orifice and subapically located ventral ostium, with particularly long apical projection of the dorsal wall. As the aedeagus within Euconnus (and other genera of Glandulariini) is extremely diverse, the copulatory organ of Euconnus (Napoconnus) kubienai does not provide any particular subgeneric or generic diagnostic character states.

Conclusions. Morphological structures of Napoconnus are similar to those of Euconnus , especially the subgenus Napochus , but the narrow metaventral intercoxal process with a pair of posteriorly directed spines excludes this taxon from Euconnus . The broad vs. narrow metaventral intercoxal process was previously adopted as a distinction between Euconnus and Sciacharis Broun, 1983 , ( Jałoszyński 2015c), genera that are similar in many other structures. However, in Sciacharis the metacoxae are contiguous and the metaventral process lacks the pair of spines, found in Napoconnus . This structure can be found in many genera of Glandulariini, but none of them has the body form so much Napochus -like as Euconnus (Napoconnus) kubienai and other species currently placed in Napoconnus ; also none of them has the antennal club composed of enlarged three terminal antennomeres. Consequently, Napoconnus is here elevated to the generic rank.

Emended diagnosis of the genus Napoconnus , status revised. Body Napochus -like, i.e., the head subpentagonal with long tempora, pronotum subtrapezoidal, broadest near base and strongly narrowing anteriorly, with lateral margins nearly straight, and oval elytra; head and pronotum with thick bristles. Antenna with distinct club composed of antennomeres IX–XI; hypostomal ridges short, strongly bent mesally and running nearly parallel to posterior margins of cardines; pronotum with faint antebasal impression and one pair of barely discernible lateral pits, lacking sublateral carinae; hypomeral ridges complete; prosternum lacking prosternal process or carina; mesoventral intercoxal process keel-like, anteriorly connected with anterior ridge of mesoventrite; metaventral intercoxal process narrowly separating metacoxae, with a pair of posteriorly directed, pointed spines adjacent at middle; each elytron with two rudimentary basal foveae; aedeagus with free parameres.

Figures

FIGURES 1 – 9. Euconnus (Napoconnus) kubienai Franz (1 – 3); Euconnus (Himaloconnus) shutjensis Franz (4 – 6); and Euconnus (Nepaloconnus) khumbuensis Franz (7 – 9). Dorsal habitus of holotype male (1, 4, 7) and aedeagus in ventral (2, 5, 8) and lateral (3, 6, 9) views.

FIGURES 10 – 12. Morphological structures of Euconnus (Napoconnus) kubienai Franz. Head, prothorax and anterior portion of pterothorax in ventral view (10); right antennal club in ventral view (11); pterothorax in ventral view (12). Abbreviations: gp, gular plate; hr, hypostomal ridge; hyr, hypomeral ridge; mn, mentum; msvp, mesoventral intercoxal process; mtvp, metaventral intercoxal process; mxp, maxillary palp; nss, notosternal suture; pcr, procoxal rest; ptp, posterior tentorial pit; smn, submentum; v 3, metaventrite.