Diglotta mersa (Haliday)

Klimaszewski, Jan, Webster, Reginald, Assing, Volker & Savard, Karine, 2008, Diglotta mersa (Haliday) and Halobrecta flavipes Thomson, two new species for the Canadian fauna (Coleoptera, Staphylinidae, Aleocharinae), ZooKeys 2 (2), pp. 175-188 : 180-182

Diglotta mersa (Haliday)

( Figs. 1-14 )

Diglossa mersa Haliday, 1837: 252 ; Good 1998: 74; Smetana 2004: 421.

Diglossa crassa Mulsant and Rey, 1870: 180 ; Smetana 2004: 421.

Diglossa submarina ( Fairmaire and Laboulbène, 1856: 468) . Lohse 1974: 20; Lohse 1985; Lohse and Lucht 1989: 115; Good 1998: 74; Smetana 2004: 421.

Description

Body length 1.9-2.1 mm, body width 0.2-0.3 mm; dark brown to almost black, with tarsi, apical portions of tibiae and apical two articles of maxillary palpi yellowish brown, abdomen slightly darker than remainder of body ( Fig. 1 ); metatarsus with 4 tarsomeres ( Fig. 11 ). Pubescence short and moderately dense, yellowish grey in artificial light. Antennae with scape elongate and as long as pedicel, about 3 times as long as wide, antennomere 3 about twice as long as wide, antennomeres 4-7 approximately subquadrate, 8-10 slightly transverse, and 11 twice as long as preceding article ( Fig. 1 ). MALE. Tergite 8 transverse, truncate apically, antecostal suture slightly pointed medially ( Fig. 5 ). Sternite 8 transverse, strongly produced apically, antecostal suture approximately straight ( Fig. 6 ). Paramere with moderately long apical lobe, its apex rectangular, two macrosetae present in subapical part ( Fig. 4 ). Median lobe of aedeagus with relatively large bulbus bearing narrow crista apicalis, tubus narrowly elongate, arched and with apical part narrow and slightly pointed ventrally, internal sac with subapical sclerites (one visible in lateral view) hooked apically ( Figs. 2, 3 ). FEMALE. Tergite 8 similar to that of male ( Fig. 7 ). Sternite 8 transverse and broadly rounded apically ( Fig. 8 ). Spermatheca with spherical capsule connected to a narrow and slightly elbowed stem ( Figs. 9, 11 ).

Distribution

Diglotta mersa has previously been reported from coastal areas of Europe: Albania, Belgium, Denmark, France, Great Britain, Germany, Ireland, Italy and the Netherlands ( Smetana 2004), but due to previous species misinterpretation ( Good 1998), the distribution in the Western Palaearctic requires revision. We report this species for the first time from the Atlantic coast of North America ( Canada: New Brunswick). Diglotta mersa is wing-dimorphic and both winged and wingless forms have been reported in Europe ( Good 1998). Th ese observations suggest that the species is capable of longdistance dispersal and may be adventive on the Atlantic coast of North America.

Collection data

Sixteen specimens were captured on 12 May 2008 on fine gravel under or adjacent to 10-15 cm rocks in the intertidal zone, approximately 2 m below the mean high tide mark ( Figs. 13 , 14 ). Rocks at this site were largely free of algae. An additional 24 specimens were found in July on sea beaches under 10-30 cm diameter rock in sand, about 4.0 m below mean high tide mark, and under 10-80 cm diameter rocks in sand, 2.0 to 5.0 m below mean high tide mark.

Material examined

CANADA, New Brunswick: Charlotte Co., Maces Bay , 45°.1242 N, 66°.4732 W, 11 July 2008, R. P. Webster, coll., sea beach, intertidal zone, under 10 cm diameter rock in sand, about 4.0 m below mean high tide mark (RWC), 1 sex undetermined ; Charlotte Co., St. Andrews , 45°.0751 N, 67°.0370 W, 12 July 2008, R. P. Webster, coll., sea beach, intertidal zone, under 30 cm diameter rock in sand, about 4.0 m below mean high tide mark (RWC), 1 sex undetermined ; Saint John Co., Dipper Harbour , 45.1154° N, 66.3720° W, 12 May 2008, leg. R. P. Webster, sea beach, intertidal zone, under rock on fine gravel, approximately 2 m below mean high tide mark (LFC, RWC), 6 males, 6 females, 4 sex undetermined ; Saint John Co., Chance Harbour off Cranberry Head Road , 45°.1348 N, 66°.3438 W, 6 July 2008, R. P. Webster, coll., sea beach, intertidal zone, under 10-80 cm diameter rocks in sand, 2.0 to 5.0 m below mean high tide mark (LFC, RWC), 21 sex undetermined .

Comments

The median lobe of the aedeagus of the holotype of Diglotta littoralis (Horn) is illustrated in Fig. 12 . Th is is the only other species of the genus occurring on the Atlantic coast of North America and it is known only from the holotype, which was collected in New Jersey. Th e median lobe of this species is presented here for the first time.

Figures

Fig. 1. Diglotta mersa (Haliday) in dorsal view. Scale bar = 1 mm.

Figs. 2-12. Diglotta mersa (Haliday): 2, median lobe of aedeagus in lateral view (New Brunswick); 3, median lobe of aedeagus in lateral view (Europe); 4, paramere (New Brunswick); 5, male tergite 8 (New Brunswick); 6, male sternite 8 (New Brunswick); 7, female tergite 8 (New Brunswick); 8, female sternite 8 (New Brunswick); 9, spermatheca (New Brunswick); 10, spermatheca (Europe); 11, metatarsus with 4 articles (New Brunswick); 12, median lobe of the aedeagus of the holotype of D. littoralis in lateral view. Scale bars = 0.1 mm.

Fig. 13. Habitat of D. mersa and H. flavipes (Chance Harbour, New Brunswick).

Fig. 14. Habitat of D. mersa and H. flavipes (near Dipper Harbour, New Brunswick).