Lathrobium (Lathrobium) sparsellum Casey, 1905

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 (Lathrobium) sparsellum Casey, 1905

Lathrobium sparsellum Casey, 1905: 87.

Lathrobium obtusum Casey, 1905: 86. New synonym.

Lathrobium postremum Casey, 1905: 88. New synonym.

Lathrobium rigidum Casey, 1905: 88. New synonym.

Type material.

Lectotype, Lathrobium sparsellum Casey, herein designated (USNM): "Winnipg. Man. / CASEY bequest 1925 / [red] TYPE USNM 38120 / [handwritten] Lathrobium sparsellum / Lectotype Lathrobium sparsellum Casey Desg. Haberski & Caterino." Lectotype, Lathrobium obtusum Casey, herein designated (USNM): "Mass/ CASEY bequest 1925 / [red] TYPE USNM 38119 / Lectotype Lathrobium obtusum Casey Desg. Haberski & Caterino." Lectotype, Lathrobium postremum Casey, herein designated (USNM): "R.I. / CASEY bequest 1925 / [red] TYPE USNM 38123 / [handwritten] Lathrobium postremum / Lectotype Lathrobium postremum Casey Desg. Haberski & Caterino." Lectotype, Lathrobium rigidum Casey, herein designated (USNM): "R.I. / CASEY bequest 1925 / [red] TYPE USNM 38122 / [handwritten] Lathrobium rigidum / Lectotype Lathrobium rigidum Casey Desg. Haberski & Caterino."

Other material.

Canada: ‘Can’ (1, USNM). Quebec: MRC des Deux-Montagnes: Parc National d'Oka , 06 May 2023, R. Vigneault, handpicked near beach (1, NBC); same data, except white tulle interception trap in composting site (1, NBC) . USA; Connecticut: New Haven Co.: New Haven (1, USNM) . Massachusetts: ‘Mass’ (2, USNM). New Hampshire: Strafford Co.: Spruce Hole Conservation Area , D. S. Chandler (1, UNHC) ; Rhode Island: 'R. I.' (4, USNM).

Diagnosis.

This species closely resembles L. simile but can be differentiated as described under the diagnosis for L. simile .

Description.

Body length 8 mm; body coloration dark, appendages lighter red. Gular sutures parallel, widely separate; antennomeres V-VII as long as wide. Elytra as long as pronotum. Females with paraprocts divided; proctiger narrow; sternite VIII weakly oblong. Male sternite VIII with narrow, deep emargination. Genitalia as in Fig. 50 .

Distribution.

Canada: AB, MB, NB, NF, NS, ON, QC ( Bousquet et al. 2013). USA: CT, MA, ME, NH, NY, RI, VT ( Newton 2022).

Remarks.

We reduce Lathrobium obtusum , Lathrobium postremum , and Lathrobium rigidum to synonymy with Lathrobium sparsellum based on the inaccuracies of the original descriptions and the inability to find alternative distinguishing characters. Lathrobium postremum and L. rigidum were differentiated from L. sparsellum based on their elytra being shorter than the pronotum, as opposed to subequal as in L. sparsellum . However, we measured Casey’s specimens and found the elytra to be subequal or slightly longer than the pronotum in all three species.

Lathrobium obtusum was distinguished from L. sparsellum primarily based on the gular sutures being "moderately separated and feebly converging" as opposed to "widely separated, almost straight" in L. sparsellum ( Casey 1905). However, we could not see a difference in suture shape, and sutures in both species were approximately equidistant. We examined the genitalia of all four species and found no morphological differences in males or females.

Figures

Figures 50 - 53. Lathrobium terminalia A female terminalia B male sternite VIII C aedeagus in ventral view D aedeagus in lateral view. 50 L. sparsellum 51 L. spissicorne 52 L. washingtoni 53 L. debile. Scale bars: 1 mm.