Mecyclothorax eyrensis (Blackburn)

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 eyrensis (Blackburn) Figures 2G, 5A, 9G, 10G, 11D, 12C, 13C, 14D

Cyclothorax eyrensis Blackburn 1892: 480.

Mecyclothorax eyrensis Csiki, 1929: 488.

Diagnosis

(n = 5). Among species of the M. lophoides complex this species stands out based on its rufous coloration (Fig. 5A), and distinctly cordate pronotum with projected, nearly right hind angles (Fig. 2G). In the most melanized specimens, the forebody–head and pronotum–may be rufopiceous, but the elytra retain rufous coloration, and the legs are pale, flavous, with a slightly smoky piceous cast. The eyes are moderately convex, MHW/mFW = 1.51-1.57, less convex than those of the other M. lophoides complex species (Figs 4, 5 B–C). The pronotum is quite constricted basally, MEW/BPW = 1.76-1.82, and moderately transverse, MEW/PL = 1.22-1.28. The pronotal lateral marginal depression is moderately broad, with the marginal bead only slightly upraised. The median base is minutely punctate, with 5-8 isolated punctures each side from midline to the ill-defined laterobasal depressions, those defined mostly by a longitudinal line of larger punctures, with several larger punctures also present between that line and the marginal bead. The hind angle is right to slightly obtuse, with the posterior margin transverse and anterad the convex median basal margin, which is smooth not beaded. The prosternum is flat to depressed medially, the medial area bearing a longitudinal series of 7 distinct punctures. The anteapical groove is deep and distinctly punctate laterally, continuous and more shallowly punctate medially, and the marginal bead of the procoxal cavity is bordered anteriorly by 5-6 strigose punctulae. The mesepisternum is covered with punctures, about 13 deep punctures arrayed in 3-4 irregular rows. The elytra are relatively broad, MEW/EL = 0.67-0.73, and flat medially on disc. Elytral striae 1-4 bear large punctures, those serial punctures close set enough on the disc to depress the intervening cuticle. Strial punctation is more strongly developed in this species than in other species of the M. lophoides complex (Fig. 12), with the sutural stria distinctly punctate mesad the posterior dorsal elytral seta. In this species cuticular microsculpture is less well developed than in the other M. lophoides complex species, with: 1, frons smooth, glossy, with micropunctures sporadically visible across surface; 2, pronotal disc glossy with sporadic micropunctures visible, very transverse lines sporadically visible laterally and near concavities of median longitudinal impression and laterobasal depression; 3, elytral discal intervals largely glossy, with shallow transverse lines sporadically visible over surface (Fig. 12C), transverse microsculpture more developed on elytral apex where it forms an elongate transverse mesh, sculpticells 3 –4× broad as long. Body coloration varies from a bright rufous, mostly in desert inhabiting beetles from the northern part of the range including the type locality of Leighʼs Creek (Fig. 11D), to darker with rufopiceous head and pronotum and rufous elytra at localities on the southern edge of the range; Mt. Remarkable and Telowie Gorge. Even in the darker specimens, the base of the pronotum is an amber rufous, the cuticle appearing translucent. Standardized body length 4.2-5.5 mm. Setal formula ++/++/+2++.

Male genitalia (n = 10). Aedeagal median lobe broadest near basal 1/3 of length, ventral margin distinctly and evenly curved (Fig. 14D); internal sac bearing a long sinuous flagellum, a large bean-shaped dorsal plate, and a well-sclerotized, smooth flagellar sheath, the sheath length less than 1/4 flagellar length (Fig. 14D, as in Fig. 14F); right paramere expanded dorsally in basal half, the dorsal margin convex, 7-11 setae along ventral margin and ~1 on dorsal margin (Fig. 13C); left paramere broadly quadrate basally, extended as a narrowly attenuated whip to apex. Comparing the dissected aedeagi of 10 M. eyrensis males (e.g. Fig. 14D) and 16 M. peryphoides males (e.g. Fig. 14E) resulted in no discernible differences in overall shape of the median lobe, in curvature or expanse of the apex, in the basal bulb or development of the sagittal crest, nor in structures of the internal sac such as the flagellum, flagellar sheath, or dorsal plate (Fig. 14 D–E). The only male genitalic differences noted between males of these two species involved the presence of fewer setae along the ventral margin of the right parameres of M. eyrensis versus M. peryphoides (e.g. Fig. 13 C–D). To determine whether these differences could diagnose the species, the numbers of setae along the ventral margin of the right paramere in 10 individuals of M. eyrensis (setal numbers: 7, 7, 8, 8, 8, 8, 9, 11, 11, 11) were compared to those in 15 individuals of M. peryphoides (setal numbers: 9, 10, 10, 11, 11, 11, 12, 12, 13, 13, 13, 14, 15, 15, 17) using the Wilcoxon rank-sum test ( Snedecor and Cochran 1980). The distribution of values resulted in a minimal T1 = 69, below the threshold value of 84 for a p = 0.01 level of significance for difference between the two distributions (Supplementary material 2). Even though the values among individuals overlap slightly in the 9-11 setal counts, there is a statistically significant difference between the setal configurations of the two species. This significant difference augments the diagnostic differences found in the external characters.

Female reproductive tract (n = 3). Bursa copulatrix short, slightly longer than broad (Fig. 9G); helminthoid sclerite broad basally, with narrow, elongate mediodistal projection; spermathecal duct elongate, sclerotized enough to hold coiled configuration, length ~2 × length of spermathecal reservoir; basal gonocoxite with 2-6 apical setae, 2-4 of those larger and the balance smaller, plus a similarly sized seta at the apicomedial angle (Fig. 10G); medial surface of basal gonocoxite with several smaller setae along length; apical gonocoxite subtriangular, narrowly rounded apically; lateral ensiform setae small, narrow; apical nematiform setae in apical sensory furrow.

Type information.

Lectotype male (BMNH) hereby designated: platen mounted with "2710 T / L. C. (red ink) // Type (round, red-margined label) // Blackburn coll. 1910-236 // Cyclothorax eyrensis Blackb. // Lectotype Cyclothorax eyrensis Blackburn / J.K. Liebherr 2006 [black-margined red label]. The abbreviation "L. C." stands for Leigh Creek based on the labels below. Paralectotype female (SAMA): platen mounted with L. C. 2710 in red ink // Leigh Ck. C.A. / Blackb’s Coll. // Cyclothorax eyrensis Bl. / Co-type // Mecyclothorax eyrensis Blkn / S. Australia / Cotype [red ink] // Paralectotype ♀ / Cyclothorax / eyrensis Blackburn / det. J.K. Liebherr 2004 [black-margined red label]. The type locality is Leigh Creek, South Australia.

Distribution and habitat.

This species is distributed across the interior of southeastern Australia (Fig. 11D), in South Australia from Telowie Gorge to Mt. Remarkable (FMNH), eastward to western N.S.W., and northward into southern Northern Territory at Palm Valley and Stokes Creek in the Gill Range (FMNH). Localities and repositories for non-type material include: NSW: Silverton (ANIC, 1). NT: Gill Range, Stokes Ck. (CUIC, 1; FMNH, 2); Palm Valley (FMNH, 1). SA: Flinders Ranges, Bunyeroo Gorge (CUIC, 1; FMNH, 14), Telowie Gorge (CUIC, 2; FMNH, 5); Mann Range, 0.5 km N Angatja Homestead (CUIC, 1; FMNH, 1); Musgrave Range, 13 km N Ernabella (CUIC, 1; FMNH, 10), 15 km W Officer Ck. (FMNH, 10), 17 km W Jacky Pass (CUIC, 1); Mt. Remarkable (CUIC, 6; FMNH, 94); Wilmington (MVM, 3); Yunta (FMNH, 3). The extensive collections made by L. Watrous (FMNH) were obtained from sieved litter or reed drift from along dry or running streams. Nonetheless, and going against Darlingtonʼs generalization for riparian species, all observed individuals are vestigially winged.