Goniusa caseyi Gusarov

Gusarov, Vladimir I., 2003, A revision of the genus Goniusa Casey, 1906 (Coleoptera: Staphylinidae: Aleocharinae), Zootaxa 164, pp. 1-20 : 9-14

1. Goniusa caseyi Gusarov , sp. n. ( Figs. 1­15 , 20­38 )

Goniusa obtusa: Casey, 1906: 348 (nec LeConte, 1866: 373) (Misidentification). Goniusa obtusa: Casey, 1911: 208 (Misidentification) .

Goniusa obtusa: Fenyes, 1920: 236 (Misidentification) .

Goniusa obtusa: Bernhauer & Scheerpeltz, 1926: 597 (Misidentification) . Goniusa obtusa: Kistner, 1976: 87 (Misidentification) .

Type material. Holotype:, UNITED STATES: Massachusetts: Middlesex Co.: 4.5 mi. W Ashby, from nest of Formica integra (mounted with a specimen of F. integra ) (A.Newton & M.Thayer), 18.iv.1976 ( FMNH).

Paratypes: UNITED STATES: Massachusetts:, (no additional locality data) ( KSEM); Middlesex Co.: 4, 4, same data as the holotype (6 specimens mounted with specimens of F. integra ) ( FMNH, SPSU); 3, ditto but 24.vii.1976 (mounted with specimens of F. integra ); (mounted with a Formica specimen), 4.5 mi. W Ashby, from ant nest under rocks (A.F.Newton), 6.v.1971;, Westford, from Formica nest under rocks (mounted with a Formica specimen) (A.Newton), 27.v.1973;, Dracut (all ­ FMNH);, Framingham (C.A.Frost);, ditto but 5.v.1912 (mounted with a Formica specimen);, Sherborn, in nest of Formica rufa (C.A.Frost) , 30.iv.1916;, Sherborn, under stones (mounted with a Formica specimen) (C.A.Frost), 4.v.1915 (all ­ CASC); Norfolk Co.: 2 (mounted with a Formica specimen), Blue Hills (W.M. Mann), 12.v.1912 ( FMNH); New Hampshire: Grafton Co.:, Rumney (mounted with a Formica specimen) (Darlington), 24.iv.1925 ( CNCI); New York: Tompkins Co.:, Ithaca, 1.viii.1884 ( FMNH); New Jersey: Mercer Co.:, Princeton (mounted with a Formica specimen), 11.v.1941 ( FMNH); District of Columbia: 2 (no additional locality data) ( CASC, KSEM); (no additional locality data) (Wickham);, Washington ( CASC); 4, 3 (3, 2 mounted with Formica specimens), Washington, iv ( FMNH; KSEM; NMNH (Casey collection)); Texas: 2, 3, (no locality data) (one female mounted with a Formica specimen) ( FMNH, SPSU); CANADA: Manitoba: 2,, Aweme (N.Criddle), 17.v.1919 ( CASC, CNCI);, Aweme, from Formica nest (N.Criddle), 2.v.1916 ( CASC);, Aweme, from ant nest (N.Criddle), 3.v.1916 ( CNCI);, Aweme (N.Criddle) ( NMNH (Casey collection));, Stonewall (J.B. Wallis), 23.iv.1970 ( CNCI).

Diagnosis. Goniusa caseyi can be distinguished from G. alperti by having pronotum with subparallel lateral sides, reaching maximum width in front of the middle ( Figs. 37­ 38 ); antennal segments 5­10 slightly elongate; larger body and longer apical process of the median lobe of aedeagus ( Figs. 26­27, 29 ).

Description. Length 3.2­4.2 mm. Head darker than the rest of the body, brownish black to brown; pronotum, elytra and abdomen light brown to reddish brown; elytra and abdominal segments 3­5 often lighter than pronotum and abdominal segments 5­7; legs, antennae and mouthparts brownish red.

In females head surface glossy, with weak isodiametric microsculpture, with strong punctation, distance between punctures equals 1/2­1 times their diameter. In males head surface matte, with strong isodiametric microsculpture, with weak, sparse and poorly visible punctation. Temple length to eye length ratio 0.6­1.0. Antennal articles 4­10 slightly elongate ( Fig. 14 ).

Pronotum strongly transverse, with subparallel lateral sides, reaching maximum width in front of the middle ( Figs. 37­38 ), 1.6 times as wide as head, width 0.94­1.07 mm, length 0.60­0.70 mm, width to length ratio 1.5; in females surface glossy, with weak isodiametric microsculpture; punctation finer than on head, distance between punctures equal to their diameter; in males surface matte, with strong isodiametric microsculpture; and fine and poorly visible punctation. Elytra slightly wider (1.01­1.21 mm) and longer (0.69­0.79 mm; measured from humeral angle) than pronotum (pronotal length to elytral length ratio 0.9), 1.5 times wider than long, surface glossy, with fine and weak isodiametric microsculpture, and with fine and slightly asperate punctation, distance between punctures equal to their diameter.

Abdominal terga glossy, with fine and often poorly visible transverse microsculpture, with fine punctation, distance between punctures equals 1­2 times their diameter on terga 3­5 and 3­6 times on terga 6­7. Apical margin of tergum 7 with white palisade fringe.

In males head with broad medial impression; pronotum with broad medial impression that is half as wide as pronotum, deeper in posterior half, postero­lateral portions of the impression with less dense microsculpture, without punctation and pubescence. Sternum 8 with wide apical emargination ( Fig. 21 ). Posterior margin of male tergum 8 crenulate ( Figs. 20, 22 ).

Aedeagus as in Figs. 25­34 .

Spermatheca as in Figs. 35­36 .

Distribution. Known from Manitoba, New Hampshire, Massachusetts, New York, New Jersey, District of Columbia and Texas ( Fig. 57 ).

Natural History. Goniusa caseyi is associated with ants of the genus Formica (e.g., Formica integra (identified by Dr. E.O.Wilson: Kistner, 1976)).

Figures

FIGURE 57. Geographical distribution of Goniusa caseyi Gusarov, sp. n. and G. alperti Kistner. Black circles and triangles indicate the localities of examined specimens. Open circles and triangles indicate the localities of additional specimens listed by Kistner (1976) but not examined by me. The exact locality of the Texas specimens of Goniusa caseyi is unknown.

FIGURES 1 ­ 5. Mouthparts of Goniusa caseyi Gusarov, sp. n. (paratype from Aweme, Manitoba). 1 – labrum; 2 – epipharynx; 3 – left mandible, dorsal view; 4 – left mandible, ventral view; 5 – right mandible, dorsal view. Scale bar 0.1 mm.

FIGURES 6 ­ 11. Mouthparts of Goniusa caseyi Gusarov, sp. n. (paratype from Aweme, Manitoba). 6 – prementum; 7 – hypopharynx; 8 – right maxilla, ventral view; 9 – right lacinia, dorsal view; 10 – right lacinia, ventral view; 11 – right galea, dorsal view. Scale bar 0.1 mm (6 ­ 7, 9 ­ 11), 0.2 mm (8).

FIGURES 12 ­ 15. Details of Goniusa caseyi Gusarov, sp. n. (paratype from Aweme, Manitoba). 12 – pronotum; 13 – meso­ and metathorax, ventral view; 14 – right antenna; 15 – mentum. Scale bar 0.1 mm (15), 0.2 mm (12), 0.4 mm (13 ­ 14).

FIGURES 20 ­ 24. Abdominal segment 8 of Goniusa caseyi Gusarov, sp. n. (paratypes from Washington, D. C. (20 ­ 21); Aweme, Manitoba (22); and Stonewall, Manitoba (23 ­ 24 )). 20 – male tergum 8; 21 – male sternum 8; 22 – apex of male tergum 8; 23 – female tergum 8; 24 – female sternum 8. Scale bar 0.4 mm (20 ­ 21, 23 ­ 24), 0.2 mm (22).

FIGURES 25 ­ 29. Median lobe of aedeagus of Goniusa caseyi Gusarov, sp. n. (paratypes from Washington, D. C. (25 ­ 26, 28 ­ 29); and Sherborn, Massachusetts (27 )). 25 – median lobe, parameral view; 26 ­ 27 – apex of median lobe, parameral view; 28 – median lobe, lateral view; 29 – apex of median lobe, lateral view. Scale bar 0.4 mm (25, 28), 0.2 mm (26 ­ 27, 29).

FIGURES 30 ­ 36. Genitalia of Goniusa caseyi Gusarov, sp. n. (paratypes from Aweme, Manitoba (30 ­ 31); Texas (32 ­ 34); Sherborn, Massachusetts (35); and Stonewall, Manitoba (36 )). 30 – everted internal sac of aedeagus, parameral view; 31 – everted internal sac of aedeagus, lateral view; 32 – copulatory piece, apical view; 33 – copulatory piece, lateral view; 34 – copulatory piece, abparameral view; 35 ­ 36 – spermatheca. Scale bar 0.1 mm (32 ­ 34), 0.2 mm (30 ­ 31, 35 ­ 36).

FIGURES 37 ­ 41. Pronotum of Goniusa caseyi Gusarov, sp. n. (paratypes from Aweme, Manitoba (37); and Stonewall, Manitoba (38 )) and G. alperti Kistner (holotype (39); female from San Bernardino Mts., California (40), paratype from 10 mi. E of Coville, Washington (41 )). 37, 39 – male pronotum; 38, 40 ­ 41 – female pronotum. Scale bar 0.5 mm.