Xenocaucus chomensis, Weirauch & Forthman & Grebennikov & Baňař, 2017

Weirauch, C., Forthman, M., Grebennikov, V. & Baňař, P., 2017, From Eastern Arc Mountains to extreme sexual dimorphism: systematics of the enigmatic assassin bug genus Xenocaucus (Hemiptera: Reduviidae: Tribelocephalinae), Organisms Diversity & Evolution (New York, N. Y.) 17 (2), pp. 421-445 : 438

Xenocaucus chomensis , n. sp.

Figures 3 , 5 , 6 , 7 , 8 , 9 , and 10.

Diagnosis Female: recognized by the large size (> 3 mm), the very short pit on vertex, the pronotal disk raised and heart-shaped, the intersegmental membranes between tergites 3 and 4 straight ( Fig. 3 ) and between tergites 7 and 8 curved ( Fig. 3 ), and the setae on lateral margin of dorsal laterotergites very long and those dorsally short ( Fig. 3 ).

Description Female: total length, 3.67 mm; total length: greatest abdominal width 1.9; wing condition and general vestiture as in generic description. Coloration: uniformly brown to reddish brown. Structure: head: about as long as wide in dorsal view, with very small genal and maxillary plate areas, glabrous area on vertex circular, pit very short, tuft absent, lateral fringes of similar length around posterior half of head. Antenna: scape length: head length 1.8, scape slender. Labium: first visible segment: head length 0.8. Thorax: transverse suture between pronotum and mesonotum distinct, pronotal disk raised with lobed, heart-shaped appearance, pronotum longer than mesonotum (ratio 1.4), greatest pronotal width: pronotal length 1.5. Legs: foretrochanter without ventral process, fore femur length: body length 0.3, forefemur fairly stout. Abdomen: slightly longer than wide, length: width 1.2, intersegmental membrane between tergites 3 and 4 straight, intersegmental membrane between tergites 6 and 7 distinctly curved anteriad, intersegmental membrane between tergites 7 and 8 curved, mediotergites 1/2 and 3 glabrous, setae on lateral margin of dorsal laterotergites very long, setae dorsally on dorsal laterotergites short. Genitalia: as in generic description.

Male: unknown. Immatures with wing pads suggest that males are macropterous.

Immatures: as in Fig. 3 .

Etymology Named for the collecting locality of the paratypes, Chome Forest in the South Pare Mountains.

Material examined holotype: Tanzania South Pare Mts. , Kwizu For., 4.12924° S, 37.88445° E, 1629 m, 7 Jan. 2013 ,

V. Grebennikov, 1;female (00020644) ( CNC). Paratypes: TANZANIA: South Pare Mts. , Chome For., 4.27064° S, 37.92595° E, 2159 m, 3 Jan. 2013, V. Grebennikov, 1;female (00020643) ( CNC) . South Pare Mts. , Chome For., 4.26945° S, 37.92814° E, 2239 m, 3 Jan. 2013, V. Grebennikov, 2;female (00020645, 00020646) ( CNC) , 2;female (00020647,00020648) ( AMNH). Other specimens examined: Tanzania : South Pare Mts., Chome For., 4.26945° S, 37.92814° E, 2239 m, 3 Jan. 2013, V. Grebennikov, 2;juvenile male (00020606, 00020607) ( CNC) . South Pare Mts. , Kwizu For., 4.12924° S, 37.88445° E, 1629 m, 7 Jan. 2013, V. Grebennikov, 1;juvenile male, (00020608) ( CNC) .

Figures

Fig. 3 Dorsal habitus of X. chomensis, n. sp., (female, unsexed immature, and male immature), X. ethiopiensis, n. sp., (male holotype and female), X. kimbozensis, n. sp., (female, unsexed immature, and male immature), the female holotype of X. mancinii, and X. nguru, n. sp., (female, unsexed immature, and male immature). dld setae dorsally

Fig. 5 Lateral habitus of females of the seven East African species of Xenocaucus and the male of X. ethiopiensis. fl flagellomeres, lb1–3 first, second, and third visible labia segments, om ommatidium, pd pedicel; scale bars, 1 mm

Fig. 6 Ventral habitus of the seven East African species of Xenocaucus and the male of X. ethiopiensis; abbreviation: vptr, ventral process on trochanter

Fig. 7 Details of the head (dorsal, lateral, and/or ventral view) of selected species of Xenocaucus

Fig. 8 Details of thorax and abdomen of a female of X. chomensis and the male holotype of X. ethiopiensis. bt bulbous trichome, msp bilobed process on metasternum, ts1,2 tarsomere 1 and 2

Fig. 9 Scanning electron micrographs of females of X. chomensis (UCR_ENT 00020646; a, b, d, h, i) and X. nguru (UCR_ENT 00020634; c, e, f, g, j, k). a Head, dorsal view; b head closeup, dorsal view; c head and thorax, lateral view; d head, lateral view; e head and