Psammostiba comparabilis

Gusarov, Vladimir I., 2003, A revision of Nearctic species of the genera Adota Casey, 1910 and Psammostiba Yosii & Sawada, 1976 (Coleoptera: Staphylinidae: Aleocharinae), Zootaxa 185, pp. 1-35 : 25-28

1. Psammostiba comparabilis (Mäklin in Mannerheim, 1853), comb. nov.

( Figs. 64 , 66, 68­77 )

Homalota comparabilis Mäklin in Mannerheim, 1853: 181.

Atheta (Metaxya) comparabilis: Fenyes, 1920: 199 (as valid species).

Atheta (Metaxya) comparabilis: Bernhauer & Scheerpeltz, 1926: 613 (as valid species). Atheta (Brundinia) comparabilis: Moore & Legner, 1975: 357 (as valid species). Philhygra comparabilis: Seevers, 1978: 266 (as valid species).

Adota comparabilis: Lohse & Smetana, 1985: 294 (as valid species).

Type material. Lectotype of Homalota comparabilis (designated by Lohse and Smetana (1985)), UNITED STATES: Alaska: Kodiak ( MZHF).

Additional material. UNITED STATES: Alaska: Kenai Peninsula Co.: 15 specimens, Homer, S shore of Homer spit, 59º36.33'N 151º25.71'W, sandy seashore, in seaweed (V.I.Gusarov), 22.vii.1998 ( AMNH, SPSU); California: Mendocino Co.: 2, Needle Rock, on beach (D.Giuliani), 6.x.1974 (UCR); CANADA: British Columbia: 2, 4, Queen Charlotte Islands, Graham Island, Toe Hill, "ex on rocks in intertidal" (J.S.Ashe), 14.vii.1988 ( KSEM);, Victoria ( CASC).

Diagnosis. Psammostiba comparabilis can be distinguished from P. kenaii by larger body, larger aedeagus with wider apex ( Figs. 73­74 ; 82­83) and larger spermatheca ( Figs. 77 ; 87).

Psammostiba comparabilis can be distinguished from the Palaearctic species of Psammostiba by the fine crenulation of the posterior margin of male tergum 8 (Fig. 69), and by the distinct shape of aedeagus ( Figs. 68 , 73­76 ) and spermatheca ( Fig. 77 ).

Description. Length 4.0­ 4.6 mm. Body black with brown legs and light brown tarsi.

Head surface matte, with strong and dense isodiametric microsculpture, with fine punctation, distance between punctures equals their diameter; in both sexes with weak medial impression. Temple length to eye length ratio 0.9­1.1. Antennal article 3 is 1.2 times as long as article 2, articles 4­10 elongate (ratios 1.5 (4­5), 1.4 (6), 1.3 (7) and 1.1 (8­ 10)), article 11 shorter than articles 9 and 10 combined ( Fig. 54 ).

Pronotum slightly transverse, 1.2 times as wide as head, width 0.80­0.89 mm, length 0.69­0.79 mm, width to length ratio 1.2; surface matte, with strong and dense isodiametric microsculpture; punctation finer than on head, poorly visible on matte background, distance between punctures equal to ½­1 times their diameter. Elytra much wider (1.10­1.30 mm) and longer (0.99­1.17 mm; measured from humeral angle) than pronotum (elytral length to pronotal length ratio 1.5), 1.1 times as wide as long, surface matte, with strong and dense isodiametric microsculpture; punctation as on pronotum.

Abdominal terga matte, with strong and dense isodiametric microsculpture, with fine punctation, punctation on terga 6­7 almost as dense as on terga 3­5, distance between punctures equals 1­3 times their diameter. Apical margin of tergum 7 with white palisade fringe.

Posterior margin of male tergum 8 with fine crenulation (Fig. 69). Posterior margin of male sternum 8 convex (Fig. 70).

FIGURES 69­72. Abdominal segment 8 of Psammostiba comparabilis (Mäklin) (male (69­70) and female (71­72) from Homer, Alaska). 69 – male tergum 8; 70 – male sternum 8; 71 – female tergum 8; 72 – female sternum 8. Scale bar 0.4 mm.

Natural History. Psammostiba comparabilis is a littoral species, common in decomposing seaweed on a beach.

Figures

FIGURES 62 ­ 64. Details of Psammostiba jessoensis (Brundin) (62 ­ 63; female from Rudnaya Pristan', Russia) and P. comparabilis (Mäklin) (64; male from Homer, Alaska). 62 – pronotum; 63 – meso­ and metathorax, ventral view; 64 – right antenna. Scale bar 0.4 mm.

FIGURES 65 ­ 68. Details of Psammostiba jessoensis (Brundin) (65, 67; males from Rudnaya Pristan', Russia) and P. comparabilis (Mäklin) (66, 68; males from Homer, Alaska). 65 – right metatarsus; 66 – left metatarsal segment 5 and metapretarsus, dorsal view; 67 ­ 68 – everted internal sac, parameral view. SS – medial pair of sclerotized structures. Scale bar 0.2 mm.

FIGURES 73 ­ 77. Genitalia of Psammostiba comparabilis (Mäklin) (male (73 ­ 76) and female (77) from Homer, Alaska). 73 – median lobe, parameral view; 74 – apex of median lobe, parameral view; 75 – median lobe, lateral view; 76 – apex of median lobe, lateral view; 77 – spermatheca. Scale bar 0.1 mm (74, 76), 0.2 mm (73, 75, 77).

FIGURES 53 ­ 57. Mouthparts of Psammostiba jessoensis (Brundin) (male from Rudnaya Pristan', Russia). 53 – labrum; 54 – epipharynx; 55 – left mandible, dorsal view; 56 – left mandible, ventral view; 57 – right mandible, dorsal view. Scale bar 0.2 mm.