Myrmecosticta Maruyama

Maruyama, Munetoshi, Matsumoto, Takashi & Itioka, Takao, 2011, Rove beetles (Coleoptera: Staphylinidae) associated with Aenictus laeviceps (Hymenoptera: Formicidae) in Sarawak, Malaysia: Strict host specificity, and first myrmecoid Aleocharini, Zootaxa 3102, pp. 1-26 : 5-6

Myrmecosticta Maruyama , gen. nov.

Type species. Myrmecosticta exceptionalis sp. nov., by present designation.

Etymology. Combination of the Greek myrmex (= ant) and stictos (= spotted), derived from the myrmecophily and the presence of a pair of deep spots (hollows) on the pronotum. The latter word also alludes to Tetrastica, a representative of the Tetrastica genus group to which Myrmecosticta belongs. Gender feminine.

Distribution. Malaysia (Borneo).

Description. Body ( Figs. 10, 11 ) myrmecoid, shining. Head ( Figs. 12–14 ) oval, depressed dorso-ventrally, with pair of deep hollows at side of gula (base of submentum), strongly constricted at base to form a “neck.” Antenna gently widened apically; segment I long, as long as II and III combined; segments IV–XI sparsely covered with pubescence. Labrum ( Fig. 19 ) much wider than long; anterior margin widely emarginate; surface sparsely covered with pseudopores. Mandibles asymmetric, strongly curved, pointed apically; right mandible ( Fig. 20 ) with a small tooth at middle of inner margin, without serration on inner side of each mandible. Maxilla ( Fig. 21 ) small, with galea and lacinia shortened; cardo slender, constricted near base, without pore; stipes small, shortened, without pore; palpifer without pore. Mentum ( Fig. 22 ) sub-pentangular with anterior margins concave; surface with 3 setae, 1 pore around middle, and with some pores around postero-medial margin. Prementum ( Fig. 23 ) with 2 real pores antero-laterally, 1 setal pore around middle, in total 4 or 5 pseudopores medially, and with a pore postero-laterally. Ligula ( Fig. 23 ) slightly bilobed; each lobe with 4 long setulae apically. Lateral lobe of ligula ( Fig. 23 ) generalized; inner margin almost straight. Labial palpus ( Fig. 23 ) with segment I short, slightly longer than wide, as long as II. Pronotum ( Fig. 15 ) oval, with a pair of depressions around middle; proventrite fully visible in lateral view. Mesoventrite ( Fig. 16 ) with anterior part constricted to connect to pronotal base. Metaventrite ( Fig. 16 ) broad; anterior intercoxal process truncate apically; mesocoxal cavity not margined. Elytra ( Fig. 10 ) together about as long as wide; posterior margins slightly convex. Legs ( Figs. 10, 11 ) long; femora and tibiae moderately covered with long setae; mid and hind tibiae curved; hind coxa ( Fig. 16 ) long, with a deep sulcus from near base to apex; hind trochanter ( Fig. 16 ) large, prominent laterally. Abdomen ( Figs. 10–11, 17–18 ) oval, strongly curved dorsally; anterior margins of tergites IV and V broadly emarginate. Male: median lobe of aedeagus ( Fig. 24 ) thin laterally; copulatory piece of inner sac with flagellum. Female: spermatheca ( Fig. 25 ) with a membranous area between apical and basal parts.

Diagnosis. This genus can easily be distinguished from other genera of Aleocharini by the myrmecoid body shape. The reasons behind the systematic placement of the genus in Aleocharini are discussed below.

Figures

FIGURES 10 – 18. Myrmecosticta exceptionalis gen. et sp. nov. (12 – 18, SEM photographs). 10, habitus, dorsal view; 11, ditto, lateral view (holotype); 12, head, pronotum and anterior part of elytra, lateral view; 13, head, dorsal view; 14, head, ventral view; 15, pronotum, dorsal view; 16, meso- and metathorax, coxae and trochanters, ventral view; 17, abdomen, dorsal view; 18, ditto, ventral view.

FIGURES 19 – 25. Myrmecosticta exceptionalis gen. et sp. nov. 19, labrum, dorsal view; 20, right mandible, dorsal view; 21, right maxilla, ventral view; 22, mentum, ventral view; 23, labium, ventral view; 24, median lobe of aedeagus, lateral view (holotype); 25, spermatheca.