Myrmecoplectus wellingtonicus 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 wellingtonicus Nomura and Leschen , new species

( Figs. 4A , 5 , 6 , 7A , C-E)

Description. Male. Body length 2.00– 2.32 mm, width 0.68–0.76 mm, elongate, thick, subcylindrical. Head slightly wider than long, widest just behind eyes, weakly narrowed anteriorly; clypeus very short, arcuate on anterior margin; frons broadly concave in median part; vertex weakly convex, with pair of round, strong dorsal tentorial pits, with short median longitudinal carinae just before occipital constriction; postgenae large, strongly angulate posteriad. Antennae short and thick, 0.68–0.70 mm in length, reaching basal margin of pronotum, relative length (width) of each antennomere from base to apex to width of antennomere I: 0.7 (1.0); 0.9 (0.8); 0.7 (0.7); 0.5 (0.7); 0.6 (0.7); 0.6 (0.7); 0.6 (0.8); 0.5 (0.8); 0.7 (0.9); 0.9 (1.1); 2.0 (1.2). Maxillary palpi each elongate and thick, reaching antennomere V in dorsal view; palpomere IV largest, nearly fusiform.

Pronotum slightly larger than head, slightly wider than long, subglobose, with complete median longitudinal and pair of short lateral longitudinal sulci, pair of large, round lateral foveae, and pair of transverse sulci connecting lateral foveae at posterior 1/3 ( Fig. 5A, B ). Elytra wider than long, sides subparallel, feebly convex, covered with minute punctures and pubescence, each elytron with humeral denticle, 2 basal foveae, and 2 longitudinal sulci; outer sulcus extending from outer basal fovea to near middle ( Fig. 5G ). Legs short and stout; mid-tibiae elongate and nearly straight, weakly angulate on inner side at apex.

Abdomen about as long as and narrower than elytra than elytra; segment IV largest, weakly broadened posteriad, transverse, with pair of narrow and parallel-sided paratergites and very small basimedian depression just behined elytra; V slightly smaller than IV; V short and transverse; VI very short, rounded posteriorly in dorsal view; tergite VIII transverse, narrowed posteriorly; sternite VIII transverse, almost U-shaped; tergite IX divided into pair of triangular sclerites; sternite IX small, nearly quadrangular.

Male genitalia bulbous, median lobe rounded at base, weakly narrowed apically, basal orifice very small, with a long and elongate spine at basal part; parameres large and asymmetrical ( Fig. 6D, E ).

Female. Body length 2.06–2.24 mm, width 0.68–0.72 mm, very similar to male but separable by mid-tibia rounded on inner side at apex and conically projecting abdomen in dorsal view. Antennae 0.64–0.70 mm in length, relative length (width) of each antennomere from base to apex to width of antennomere I: 0.9 (1.0); 0.9 (0.9); 0.6 (0.8); 0.6 (0.8); 0.6 (0.8); 0.6 (0.8); 0.6 (0.8); 0.6 (0.9); 0.6 (1.0); 0.7 (1.1); 1.9 (1.4). Abdominal tergite VIII nearly triangular, narrowed posteriorly with round process near posterior end; sternite VIII nearly triangular; genital plate wider than long, membranous in posterior part, with small sclerite at middle.

Remarks. This new species is characterized by the large, stout body with relatively short, thick antennae. It can be distinguished from Myrmecoplectus attenuatus new species by the form of abdominal tergite VIII, which does not have a conical projection.

Distribution. North Island. Bay of Plenty (BP), Wellington (WN).

Host Ant. Austroponera castanea (Ponerinae) .

Specimens Examined. Holotype, male (card mounted with genitalia on separate acetate label), New Zealand WN Tinakori Hill 19. Vii. 1991 // In decayed wood // HOLOTYPE Staphylinidae , Pselaphinae Myrmecoplectus wellingtonicus Nomura et Leschen S. Nomura det., 2013 [red label]. Paratypes: BP: 24. iv. 1987, J. T. Nunn leg.; 1 male, Motu R mouth (ant: Mesoponera [= Austroponera castanea ]), 19. iv. 1987, J. T. Nunn leg.; WN: 1 male, same data as holotype; 1 female, Waioeka Gorge (ant: Mesoponera [= Austroponera castanea ]), Tinakori Hill (in ants’ nest), Wellington, 30. viii. 1991 [J. T. Nunn]; 1 male, Rimutaka FP, Catchpool Stm., 19. iv. 1991 [J. T. Nunn]; 1 male, Tinakori Hill (in dead wood), Wellington, 14. i. 1991 [J. T. Nunn]; 1 male, same locality as above (in much decayed Ganoderma fungus), 3. xi. 1991 [J. T. Nunn]; 1 male, Elsdon (in decayed wood), Porirua SR, 18. ix. 1993 [J. T. Nunn]; 1 female, Karori Reservoir (in ants’ nest), 5. xi. 1994 [J. T. Nunn]; 1 female, same locality as above, 30 xi. 1994 [J. T. Nunn]; 2 males, 3 females, same locality as above (in decayed wood), 8. i. 1995 [J. T. Nunn]; 1 female, Wilton Bush, Wellington, 7. xi. 1995 [J. T. Nunn]; 6 males, 3 females, Paraparaumu (in humified Kohekohe log on forest floor), Nikau Reserve, 1. ix. 1996 [J. T. Nunn].

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.