Lathrobium (Lathrobioma) tenue LeConte, 1863

Haberski, Adam & Caterino, Michael S., 2024, A review of Nearctic Lathrobium (Coleoptera, Staphylinidae), with revision and descriptions of new flightless species from the mountains of the southeastern U. S., ZooKeys 1198, pp. 193-277 : 193

Lathrobium (Lathrobioma) tenue LeConte, 1863

Lathrobium tenue LeConte, 1863: 44.

Lathrobioma tenuis Casey, 1905: 101.

Lathrobioma hespera Casey, 1905: 100. New synonym.

Lathrobium (Lathrobioma) hesperum : Bernhauer and Schubert 1912: 261

Lathrobioma nigrolinea Casey, 1905: 102. New synonym.

Lathrobium (Lathrobioma) nigrolinea : Bernhauer and Schubert 1912: 264.

Lathrobium (Lathrobioma) nigrolineum : Blackwelder 1939: 108.

Lathrobioma oregona Casey, 1905: 102. New synonym.

Lathrobium (Lathrobioma) oregonum Bernhauer and Schubert 1912: 264.

Lathrobioma shoshonica Casey, 1905: 99. New synonym.

Lathrobium (Lathrobioma) shoshonicum Bernhauer and Schubert 1912: 267.

Type material.

Lectotype, Lathrobioma tenuis Casey, herein designated (MCZ): Pink Disc / "[handwritten] L. tenue Lec. / [red] Type 6452 / Lectotype Lathrobium tenue LeConte Desg. Haberski & Caterino." Lectotype, Lathrobioma hespera Casey, herein designated (USNM): "Br.C/ CASEY bequest 1925 / [red] TYPE USNM 38140 / Lectotype Lathrobioma hespera Casey Desg. Haberski & Caterino." Lectotype, Lathrobioma nigrolinea Casey, herein designated (USNM): "Winnipeg Man./ CASEY bequest 1925 / [handwritten] Lathrobioma nigrolinea / [red] TYPE USNM 38141 / Lectotype Lathrobioma nigrolinea Casey Desg. Haberski & Caterino." Lectotype, Lathrobioma oregona Casey, herein designated (USNM): "Port Oreg/ CASEY bequest 1925 / [handwritten] Lathrobioma oregona / [red] TYPE USNM 38142 / Lectotype Lathrobioma oregona Casey Desg. Haberski & Caterino." Lectotype, Lathrobioma shoshonica Casey, herein designated (USNM): "Or. / ♂ / CASEY bequest 1925 / [handwritten] Lathrobioma shoshonica / [red] TYPE USNM 38138 / Lectotype Lathrobioma shoshonica Casey Desg. Haberski & Caterino."

Other material.

Canada: Ontario (3, MCZ). USA: Colorado: Alamosa (1, MCZ) . Connecticut: New Haven (1, USNM) . Michigan: ‘Mic.’ (1, MCZ) . Oregon: ‘Oreg’ (1, USNM) . Rhode Island: ‘R.I.’ (7, USNM). Virginia: Highland Co.: Water Sinks, Lucas Tract , 04 May 2019, C. Harden, gravel stream bank (1, CUAC) . West Virginia: Pocahontas Co.: Cranberry Wilderness, Monongahela National Forest , 11 Jun 2019, C. Harden, under rock near stream in spruce/hardwoods (1, CUAC) .

Diagnosis.

Males of L. tenue have a broadly rounded and symmetrical ventral process of the aedeagus that is unique among Lathrobioma spp. Females are difficult to differentiate from L. othioides , but their gonocoxites are narrower and concave in the basal half.

Description.

Body length 6 mm; coloration dark, appendages yellow or light red. Gular sutures arcuate; maxillary palpomere III> 0.4 × as wide as long; antennomeres V-VII as long as wide. Elytra at least as long as pronotum, sometimes longer and wider. Females with paraprocts undivided, apices shorter than basal portion; sternite VIII weakly oblong. Ventral process of aedeagus broadly rounded (Fig. 33 ).

Distribution.

Canada: BC, MB, ON, QC, SK (Bousquet et a. 2013). USA: CO, CT, ID, MA, MI, NY, OR, RI, VA, WA, WV ( Newton 2022).

Remarks.

We reduce Lathrobium hesperum , Lathrobium oregonum , Lathrobium nigrolinea , and Lathrobium shoshonicum to synonymy with Lathrobium tenue due to insufficient morphological differences between species. Lathrobium shoshonicum and L. hesperum were described as having elytra longer than their pronota, in contrast to L. tenue which supposedly had elytra shorter than their pronota. However, upon measuring the type specimen and those in Casey’s collection, we found L. tenue also has elytra longer than its pronotum.

Lathrobium oregonum and L. nigrolinea were differentiated primarily on the shape of the emargination of male sternite VIII. In these species, the setae at the tips of the emargination are inflexed, rather than diverging as in L. tenue . This difference was based on a single male of each species and could represent normal variation, regional difference, or coincidence.

We examined the genitalia of all five species and found no differences.

Subgenus Lathrobium Lathrobium s. str.

Litolathra Casey, 1905: 71.

Lathrobium (Litolathra) : Bernhauer and Schubert 1912: 40.

Figures

Figures 29 - 34. Lathrobium terminalia A female terminalia B male sternite VIII C aedeagus in ventral view D Aedeagus in lateral view. 29 L. divisum 30 L. nanulum 31 L. othioides 32 L. scolopaceum 33 L. tenue 34 L. amplipenne. Scale bars: 1 mm.