Myrmecoplectus Nomura and Leschen, 2015

Nomura, Shûhei & Leschen, Richard A. B., 2015, Myrmecophilous Pselaphinae (Coleoptera: Staphylinidae) from New Zealand, The Coleopterists Bulletin 69 (1), pp. 121-152 : 121-152

Myrmecoplectus Nomura and Leschen , new genus

( Figs. 4–7 )

Type species: Myrmecoplectus wellingtonicus , new species.

Diagnosis. Body medium-sized (2.00– 2.32 mm), robust, subcylindrical. Head slightly narrower than prothorax and slightly wider than long, frons weakly concave, gently convex at vertex with pair of welldemarcated, setose, round dorsal tentorial pits; posterior constriction slightly notched and lacking lateral foveae; postgenae large, strongly angulate posteriad, venter weakly bearded ( Fig. 5C ). Eyes small, ovoid, and visible in dorsal view ( Fig. 5A, B ). Antennae short and thick with insertions hidden in dorsal view; antennal tubercles weakly defined. Maxillary palpi elongate; palpomere IV largest, nearly fusiform ( Fig. 5D ).

Pronotum slightly wider than head, wider than long, subglobose, with complete median sulcus, pair of lateral longitudinal sulci, and well-demarcated bisinuate antebasal sulcus ( Fig. 5A, B ). Elytra wider than long, weakly convex dorsally, each elytron with 2 basal foveae, well-developed humeral denticle, and 2 longitudinal sulci; outer longitudinal sulcus extending from outer basal fovea to near middle ( Fig. 5A, B ). Prosternum with median longitudinal carina, lateral carinae absent. Ventral foveae simple, those present as follows: gula (head); lateral procoxal (prosternum); small prepectal, lateral mesoventral, and fused median mesoventral and lateral mesocoxal (mesoventrite); lateral metaventral (metaventrite); weak mediobasal and basolateral (abdominal sternite III). Legs short and stout; 1 tarsal claw present.

Abdomen about as long as elytra, slightly narrower than elytra, with tergites equal in length, rounded posteriorly in male, conically projecting in female; sternite III very short. Male genitalia asymmetrical and bulbous, median lobe with long spine or strut at base ( Fig. 6D, E ).

Remarks. This new genus is very closely related to the New Zealand endemic genus Euplectopsis , sharing with it the pronotum with a complete median longitudinal sulcus and the prosternum with a median longitudinal carina. Myrmecoplectus can be distinguished from other similar-looking genera by the large, robust, and stout body, the angulate postgenae (round postgenae in Zeadalmodes ), and the elytra each with two basal foveae (four in Euplectopsis ).

Myrmecoplectus and Zeadalmodes share several characters in common. A bisinuate antebasal sulcus is shared with some New Zealand (e.g., some species of Euplectopsis and Whitea Hutton ) and Australian forms, including members of the informal Kioloa group ( Chandler 2001), which includes the myrmecophile Ramussia Chandler. Ramussia differs from New Zealand taxa by having a deep v-shaped vertexal fovea on the head, lacking lateral sulci on the pronotum, and it has three basal elytral foveae.

Etymology. The new name of this genus was formed from a combination of the Latin word “ Myrmeco- ” meaning ant-loving and the suffix of allied genera “ -plectus ”.

Figures

Fig. 4. Myrmecoplectus species, habitus. A) M. wellingtonicus, male paratype, B) M. attenuatus, female holotype.

Fig. 5. Myrmecoplectus wellingtonicus. A) Male head and prothorax, dorsal view, B) Female head and prothorax, dorsal view, C) Male head and prothorax, ventral view, D) Male maxillary palpus, ventral view, E) Male left antenna, dorsal view, F) Female left antenna, dorsal view, G) Left elytron, dorsal view, H) Abdomen, dorsal view.

Fig. 6. Myrmecoplectus wellingtonicus. A) Tergite VIII, B) Sternite VIII, C) Tergite IX (two lateral plates) and sternite IX (middle plate), D) Genitalia, ventral view, E) Genitalia, lateral view. Scale = 0.1 mm.

Fig. 7. Myrmecoplectus species, females. A) M. wellingtonicus, abdominal segment VIII, lateral view, B) M. attenuatus, abdominal segment VIII, lateral view. M. wellingtonicus: C) Tergite VIII, D) Sternite VIII, E) Genital plate. M. attenuatus: F) Tergite VIII, G) Sternite VIII, H) Genital plate. Scale = 0.1 mm.