Mecyclothorax cordicollis (Sloane)

Liebherr, James K., 2018, Taxonomic review of Australian Mecyclothorax Sharp (Coleoptera, Carabidae, Moriomorphini) with special emphasis on the M. lophoides (Chaudoir) species complex, Deutsche Entomologische Zeitschrift 65 (2), pp. 177-224 : 177

Mecyclothorax cordicollis (Sloane) Figures 2I, 5C, 9I, 10I, 11E, 12E, 13E, 14 G–H

Cyclothorax cordicollis Sloane 1900: 563.

Mecyclothorax cordicollis Csiki, 1929: 488.

Diagnosis

(n = 5). This species (Fig. 5C) and M. lophoides (Fig. 4 C–D) include the smallest-bodied, most gracile beetles in the M. lophoides species complex, with standardized body length for this species = 4.0-4.7 mm. Individuals exhibit a flavous marginal band on the elytra, brunneous to rufobrunneous body, and pale, flavous legs. The pronotum is very similar to that of M. lophoides (Fig. 2F, I); moderately transverse, MPW/PL = 1.17-1.24, and basally constricted, MPW/BPW = 1.62-1.68, these values broadly overlapping those calculated from specimens of M. lophoides . The eyes are also similar in configuration in the two species: here MHW/mFW = 1.63-1.71, with the eyes covering most of the ocular lobe, EyL/OLL = 0.86-0.91. The pronotal lateral marginal depression is slightly broader in this species than in M. lophoides , with microsculpture evident in its deepest part. The pronotal hind angles are obtusely rounded, with the margin behind the angle smoothly curved onto median base. The marginal bead terminates at the laterobasal depression just mesad the hind angle, and the bead is only slightly broader at the setal insertion. The pronotal median base is covered with 10-13 large isolated punctures present each side of midline. The laterobasal depression is defined by a medially arcuate line of punctures commencing at the termination of the marginal bead mesad the basal seta. The prosternum is medially depressed from the prosternal process anterad slightly less than 1/2 the distance to the anterior margin, the depression broader anteriorly, and lined with ~8 pits. The anteapical groove is punctate laterally, continuous and indistinctly punctate medially, and the procoxal cavity marginal bead is bordered by 4-5 small punctures along its anterior margin. The mesepisternum is variously punctate, the deepest portion covered with about 9 shallow to deep punctures arranged in 2-3 dorsoventral rows. The elytra are broad basally, subparallel, and broad relative to their length (Fig. 5C), MEW/EL = 0.69-0.71, versus values of 0.64-0.69 for individuals of M. lophoides (Fig. 4 C–D). The elytral disc is flat, with the sutural intervals apically raised into a callus. Elytral striae 1-6 are distinctly punctate on the disc, with the punctures nearly contiguous on the inner striae, however the intervening intervals are nearly flat. As in the other M. lophoides complex species, strial punctures are smaller and therefore further apart along the lateral striae, though in this species stria 6 is indicated until posterad midlength. As in M. peryphoides , the sutural stria is indistinctly punctate mesad the posterior dorsal elytral seta (Fig. 12 D–E), but the punctures in striae 2-4 are more well developed, agreeing with M. eyrensis , but not M. lophoides (Fig. 12 B–C). Coincident with the presence of a flavous marginal band on the darker elytra, other body coloration tends toward the polychromatic: 1, elytral epipleura dorsally flavous versus ventrally rufobrunneous adjacent to the metepisternum; 2, coxae dark brunneous, trochanters rufous, femora flavous, and tibiae and tarsomeres brunneous with smoky cast. Cuticular microsculpture includes: 1, vertex glossy with an indistinct transverse mesh in parts; 2, pronotal disc glossy with an elongate transverse mesh restricted to transverse wrinkles, and a shallow elongate transverse mesh on the median base, sculpticells more irregular in the laterobasal depression; 3, elytral disc with a shallow, elongate transverse mesh, sculpticell breadth 3 –4× length, the convex apex covered with traceable transverse lines, the entire elytral surface subiridescent. Setal formula ++/++/+2++.

Male genitalia (n = 13). Aedeagal median lobe of moderate dorsoventral breadth (Fig. 14G), evenly curved as in M. lophoides (Fig. 14A); flagellar complex including a very short, spine-like flagellum, a bifurcated flagellar sheath, and a lightly sclerotized, ovoid dorsal plate (Fig. 14H); right paramere broader basally, conchoid, with ~12 setae along ventral margin and 2-3 small setae on dorsal margin (Fig. 13E); left paramere broadest basally, but evenly narrowed to whiplike apex, the apex flexible and often twisted relative to base when aedeagus mounted on slide.

Female reproductive tract (n = 1). Bursa copulatrix squat, as broad as long (Fig. 9I); helminthoid sclerite broad basally, with narrow elongate mediodistal projection; spermathecal duct straight and narrow, evenly sclerotized, of similar length to spermathecal reservoir; basal gonocoxite with 2-3 apical setae, 2 larger setae laterally, and a moderately sized seta at the apicomedial angle (Fig. 10F); apical gonocoxite subtriangular, narrowly rounded apically; 1-2 small lateral ensiform setae present; apical nematiform setae in apical sensory furrow.

Type information.

Lectotype male (ANIC) hereby designated: 2nd specimen from left on 6-specimen platen, specimen annotated "♂ -w", male genitalia dissected and placed in polyethylene genitalia vial below labels // Cyclothorax Type / cordicollis Sl. MSS. / Colombo Plains 11/6/95 // C. cordicollis Sl. / Holotype / PJD not HT JKL 18 [pink label with Holotype crossed out] // ANIC Database / 25 014958 // ANIC Specimen [green label] / ANIC Image [orange label] // Lectotype / Cyclothorax / cordicollis / J.K. Liebherr 2017 [black-margined red label] / Mecyclothorax / cordicollis / (Sloane) ♂LT / det. J.K. Liebherr 2018. Although P.J. Darlington labelled these specimens as “Holotype”, a lectotype must be designated given Sloaneʼs description stating the multiple localities given as “Queensland–Brisbane (sent by Mr. Lea); N.S. Wales–Clarence River and Windsor (Lea), Grenfell, Junee, Urana, Mulwala (Sloane); Victoria–Ferntree Gully and Lilydale (Sloane) ( Sloane 1900: 564)." Columbo Creek [Colombo Plains sic] is near and northwest of Lake Urana and the town of Urana, and so these specimens would correspond to the “Urana” locality of Sloaneʼs list. Moreover, Sloane wrote regarding the habits of these beetles; "Found in damp situations near water, usually rare, but on July 11th, 1895, I found it very plentifully under sticks along the edge of a swamp about 20 miles north from the town of Urana ( Sloane 1900: 564)." As the label clearly reads “11/6/95” and Sloane wrote of "July 11th, 1895", some ambiguity concerning the date of this collection remains [though the label data would hold precedence]. However no such ambiguity can be countenanced regarding this collecting locality.

Distribution and habitat.

Sloane (1900) described this species from specimens representing much of the distributional range as now known augmented by more than another century of collections (Fig. 11E), with the single notable exception of two specimens collected by the Darlingtons, ii– 1958, at Ravenshoe, W of the Atherton Tableland (MCZ, 2). Localities and repositories of other non-type specimens include: NSW: Bodalla (CUIC, 1; MCZ, 10); Gosford (MVM, 2); Narrandera (MCZ, 1); Sydney vic. (CUIC, 1; MCZ, 15); QLD: Blunder (ANIC, 1); Brisbane vic. (CUIC, 2; MCZ, 9); Dalby (ANIC, 2); VIC: Dandenong Vy. (ANIC, 2); Lilydale (ANIC, 1); Melbourne (ANIC, 1); Powlett R. (ANIC, 1).

Sloaneʼs perspicacity with regard to species boundaries is very evident in his sorting out this taxon from the very similar appearing beetles of M. lophoides and M. peryphoides . What we know about the habits of this species can be taken from Sloaneʼs description, quoted above. The species is uniformly represented by vestigially winged individuals with the exceptions of macropterous beetles from two Queensland localities: 1, one of two beetles from Ravenshoe; and 2, two of two specimens from Dalby.