Horologion speokoites Valentine, 1932

Harden, Curt W., Davidson, Robert L., Malabad, Thomas E., Caterino, Michael S. & Maddison, David R., 2024, Phylogenetic systematics of the enigmatic genus Horologion Valentine, 1932 (Coleoptera, Carabidae, Trechinae, Horologionini), with description of a new species from Bath County, Virginia, Subterranean Biology 48, pp. 1-49 : 1

Horologion speokoites Valentine, 1932

Figs 1 , 7 , 8C , 9A-C , 11A

Material examined.

Holotype male (USNM), glued to clear plastic point with bit of wax on pin below point. Right metatibia and metatarsus missing. Right antenna (except for scape and pedicel) and right protibia (except for base) and protarsus removed. Two plastic cards with blocks of Canada balsam pinned beneath specimen, the top one containing genitalia and the bottom one containing the right antenna, protibia and protarsus. Original labels (Fig. 7 ): “Arbuckle’s Cave Maxwelton, W.Va. July 12 1931 J.M. Valentine " "On bit of wet decaying wood, muddy floor of lower level" " ♂ Type gen. Type sp. [red paper]" "U.S.N.M. TYPE 44255 [red paper]" “23” " Horologion speokoites Valentine detVal. 1932 HOLOTYPE [white label with red line drawn on each side]" "USNMENT [QR Code] 01374911".

Diagnosis.

The lone specimen of this species differs from H. hubbardi in the following characters: the carinal shelf of the humerus is shorter and does not end in a prominent curved spine; the elytral disc is more convex, though not nearly as convex as in Valentine’s (1932) illustration (his fig. 2) of the lateral aspect (Suppl. material 3: fig. S2B); the two basal protarsomeres are not as strongly expanded and only the first is dentate on the inner margin, slightly so (Fig. 8C ); the parameres are broader and bear more than three apical setae (Fig. 9B ); the median lobe is more strongly curved ventrally (Fig. 9A ) and is slightly bent asymmetrically in dorsal aspect (Fig. 9C ); and the flagellum has a distinct sinuation (Fig. 9C ).

Notes.

Our examination of the type of H. speokoites revealed that the specimen differs from Valentine’s description and drawings in several important characters. The first protarsomere is asymmetrical and distinctly dentate on the inner margin, and the second is slightly asymmetrical though not dentate (Fig. 8C ). The third protarsomere, which Valentine considered expanded, is the same shape as in female specimens of H. hubbardi (Fig. 8B ), and should therefore not be considered modified. The right elytron bears a prominent discal seta in the third interval. At 100 ×, using a Leica M125 stereoscope with strong diffuse light directed from the posterior of the specimen, both the pore at the base of the discal seta on the right elytron and the pore (without seta) on the left elytron were clearly visible, and both were located just posterior to the level of the fourth umbilicate puncture. The carinae that Valentine illustrated extending from the humeri onto the disc of the elytra do not exist; the disc in this region is smooth, and the humeral carinae end well before the level of the parascutellar setae. The plastic on which the genitalia are mounted in balsam is roughly textured, and the structures are heavily cleared. We were unable to study them in right lateral or dorsal aspects. The ventral margin of the median lobe appears to not be as strongly curved as Valentine’s drawing suggests, but due to the condition of the preparation and the fact that the parameres are still attached, we are unable to discern the true shape of the median lobe. Our examination of the specimen also confirms Valentine’s (1932) original report of the collection date; in the literature, the year of the collection has been variously reported as “1931” ( Valentine 1932), “1930” ( Barr 1994) and “1938” ( Culver et al. 2012).

Figures

Figure 1. Horologion speokoites holotype (USNM), dorsal habitus. Scale bar: 1 mm.

Figure 7. Labels of Horologion speokoites holotype, USNM.

Figure 8. Protarsi of Horologion A H. hubbardi male holotype, dorsal aspect B H. hubbardi female paratype, dorsal aspect C H. speokoites male holotype, dorsal aspect D H. hubbardi male holotype, ventral aspect E H. hubbardi male holotype, dorsal aspect. Scale bars: 0.10 mm.

Figure 9. Genitalia of Horologion species A H. speokoites median lobe, left lateral aspect B H. speokoites left paramere, left lateral aspect C H. speokoites median lobe, dorsal aspect D H. hubbardi median lobe, left lateral aspect E H. hubbardi left paramere, left lateral aspect F H. hubbardi median lobe, dorsal aspect G H. hubbardi right paramere, right lateral aspect H H. hubbardi female genitalia, ventral aspect A-C after Valentine (1932). Scale bar: 0.1 mm.

Figure 11. Elytral characters of Horologion species A H. speokoites holotype, elytra, oblique left lateral aspect B H. hubbardi paratype (CMNH), ditto C H. hubbardi paratype (VMNH), SEM detail of apex of left elytron, ventral aspect D H. hubbardi paratype (VMNH), SEM photo of right elytron, dorsal aspect E H. hubbardi paratype (VMNH), SEM detail of right elytron (area indicated by black box in D). Black arrows: discal setae, white arrows: plica.