Lathrobium (Lathrobium) confusum LeConte, 1880

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) confusum LeConte, 1880

Lathrobium confusum LeConte, 1880: 176.

Litolathra confusa (LeConte, 1880): Casey 1905: 96.

Litolathra amputans Casey, 1905: 95. New synonym.

Lathrobium (Litolathra) amputans : Bernhauer and Schubert 1912: 255.

Litolathra convictor Casey, 1905: 95. New synonym.

Lathrobium (Litolathra) convictor : Bernhauer and Schubert 1912: 257.

Litolathra inornata Casey, 1905: 96. New synonym.

Lathrobium (Litolathra) inornatum : Bernhauer and Schubert 1912: 261.

Litolathra suspecta Casey, 1905: 97. New synonym.

Lathrobium (Litolathra) suspectum : Bernhauer and Schubert 1912: 268.

Type material.

Lectotype, Lathrobium confusum LeConte, herein designated (MCZ): White disc / "[handwritten] L. confusum Lec. / [handwritten] 8117 / [red] Type 6456 / Lectotype Lathrobium confusum LeConte Desg. Haberski & Caterino." Lectotype, Litolathra amputans Casey, herein designated (USNM): "Ia. / CASEY bequest 1925 / [red] TYPE USNM 38132 / [handwritten] Litolathra amputans / Lectotype Litolathra amputans Casey Desg. Haberski & Caterino." Lectotype, Litolathra convictor Casey, herein designated (USNM): "City ham / CASEY bequest 1925 / [red] TYPE USNM 38130 / [handwritten] Litolathra convictor / Lectotype Litolathra convictor Casey Desg. Haberski & Caterino." Lectotype, Litolathra inornata Casey, herein designated (USNM): "Wshngtn D.C. / CASEY bequest 1925 / [red] TYPE USNM 38133 / [handwritten] Litolathra inornata / Lectotype Litolathra inornata Casey Desg. Haberski & Caterino." Lectotype, Litolathra suspecta Casey, herein designated (USNM): "N.Y. / ♂ / CASEY bequest 1925 / [red] TYPE USNM 38131 / [handwritten] Litolathra suspecta / Lectotype Litolathra suspecta Casey Desg. Haberski & Caterino."

Other material.

USA: Connecticut: New Haven Co.: New Haven (5, USNM) . Massachusetts: ‘Mass’ (4, USNM) . New Hampshire: Strafford Co.: Cooper Cedar Woods 1mi SE New Durham, 15 Aug 1982, D. S. Chandler, cedar swamp litter (1, UNHC); Strafford Co. : Foss Farm Rd water tower, 22 Oct 1982, W. J. Morse (1, UNHC); same data, except 30 Aug 1982 (3, UNHC); Strafford Co. : Spruce Hole Conservation Area 3 mi SW Durham, 09 Jun 1982, D. S. Chandler, litter on bog edge (12, UNHC); Strafford Co. : 1 mi SW Durham, 30 Oct 1982, W. J. Morse (4, UNHC) . New Jersey: Mercer Co.: Princeton , 07 Jun 2021, A. Deczynski (1, CUAC) . New York: 'N. Y.' (4, USNM); 'skill NY’ [= Catskills] (1, USNM); Yates Co.: Dundee (1, USNM) . North Carolina: Henderson Co.: Bearwallow Mountain, 10 Aug 2021, M. Caterino, A. Haberski, flood debris (1, CUAC); Jackson Co. : 6 km S Cashiers, 20 Jun 1986, A. Smetana (1, CNC) . South Carolina: Pickens Co.: Clemson , 07 May 1940 (1, CUAC) . Virginia: Shenandoah Co.: George Washing National Forest, Crooked Run Rd , Rte 720, 17 Mar 2019, C. harden, litter/duff along stream in laurel hardwoods (1, CUAC); Shenandoah Co. : George Washing National Forest , Dead Deer Creek near Signal Knob, 01 May-31 May 2015, C. Harden, flood debris (1, CUAC); Shenandoah Co. : George Washing National Forest , Rte 678 2 mi S jct w/619, 03 Jul 2018, C. Harden (1, CUAC); Shenandoah Co. : Passage Creek near Elizabeth Furnace Recreational Area , 20 Mar 2017, C. Harden, flood debris (1, CUAC); Highland Co. : Locust Springs, George Washing National Forest , 28 Jul 2017, C. Harden (3, CUAC); Smyth Co. : Mount Rogers , 15 Jun 2019, C. Harden (1, CUAC); Smyth Co. : Whitetop Mountain , 16 Jun 2019, C. Harden, litter along stream (1, CUAC); Powhatan Co. : Powhatan State Park , 02 Apr 2017, C. Harden, wetlands, nr vernal pool (1, CUAC) ; Washington D. C.: ' D. C. ' (1, USNM). West Virginia: Pocahontas Co.: Cranberry Wilderness, Monongahela National Forest , 11 Jun 2019, C. Harden, under rock nr steep stream in spruce/hardwoods (1, CUAC); Pocahontas Co. : Gaudineer Knob Scenic Area , 29 Jun 2017, C. Harden (2, CUAC); Pocahontas Co. : Kennison Mountain FS Rd 232, 20 May 2018, C. Harden, litter nr rushing ephemeral rivulet (1, CUAC); Pocahontas Co. : Pocahontas Trail near Cranberry Mountain Lodge , 10 Sep 2017, C. Harden (1, CUAC) .

Diagnosis.

Lathrobium confusum superficially resembles Lathrobioma , although it is not closely related. It differs from all Lathrobioma by having long antennomeres, and males lack the thick black setae on sternite VIII that are characteristic of the subgenus. Lathrobium confusum is more closely related to L. rhodeanum , with which is shares characteristically long antennomeres and paraprocts. The two can be distinguished by the hind tarsomeres which are shorter and more compact in L. confusum .

Description.

Body length 6 mm; coloration dark, appendages light yellow. Gular sutures arcuate (Fig. 1C ); antennomeres V-VII longer than wide. Elytra approximately as long as pronotum. Male sternite VIII with shallow notch and no thick setae; Female with paraprocts undivided, apices 2.6 × longer than basal portion, sternite VIII conical; genitalia as in Fig. 36 .

Distribution.

Canada: ON, NB, QC ( Bousquet et al. 2013). USA: CT, DC, IA, MA, NH, NJ, NY, NC, SC, VA, WV.

Remarks.

We reduce Lathrobium amputans , Lathrobium convictor , Lathrobium inornatum , and Lathrobium suspectum to synonymy with Lathrobium confusum , because the characters given by Casey (1905) were either inaccurate or insufficiently distinctive. Lathrobium amputans was described as having elytra shorter than wide in females, and those of L. confusum were said to be subequal. Upon measuring the types, we found the elytra to be subequal in length and width in both species. Lathrobium convictor was described as having elytra equal in length to the pronotum, and those of L. confusum were described as shorter than the pronotum, but we found the elytra of both species were 1.1-1.2 × longer than the pronotum.

Lathrobium inornatum was described as having the emargination of sternite VIII smaller, shallower, and more broadly rounded compared to that of L. confusum , but we found no differences in width or depth. The difference in shape was modest and the emargination of L. amputans was actually less round than that of L. confusum .

Lathrobium suspectum and L. confusum were differentiated based on obscure minutia such as form "moderately stout" vs "rather stouter", pronotal punctures "fine and moderately sparse" vs "moderately coarse and sparse," but these differences were not observed in the types ( Casey 1905). The length of the antennae relative to the head and pronotum combined were supposedly shorter in L. suspectum , but this too proved incorrect when measured.

We examined the genitalia of the above species and found no differences in aedeagi or female terminalia.

Figures

Figure 1. Lathrobium gular sutures A L. simile B L. amplipenne C L. islae D L. debile.

Figures 35 - 40. Lathrobium terminalia A female terminalia B male sternite VIII C aedeagus in ventral view D aedeagus in lateral view. 35 L. armatum 36 L. confusum 37 L. crurale 38 L. fauveli 39 L. fulvipenne 40 L. geminum. Scale bars: 1 mm.