Mecyclothorax ducalis (Sharp)

Liebherr, James K., 2015, The Mecyclothorax beetles (Coleoptera, Carabidae, Moriomorphini) of Haleakala-, Maui: Keystone of a hyperdiverse Hawaiian radiation, ZooKeys 544, pp. 1-407 : 257-258

Taxon classification Animalia Coleoptera Carabidae

(103) Mecyclothorax ducalis (Sharp) Figs 133D, 136C, 137C, 138D, 139

Thriscothorax ducalis Sharp 1903:266; Swezey 1954: 7 ( koa associate).

Mecyclothorax ducalis , Britton 1948b: 140.

Diagnosis.

This large bodied species, standardized body length 6.0-6.7 mm, also stands out from other species in the group by the dark glossy, rufopiceous body color and contrasting flavous femora and infuscated tibiae. The pronotum is less constricted basally than in the other Haleakalā species of the group, MPW/BPW = 1.43-1.46, and the elytra are broadly subquadrate, with laterally extended basal margins outside the tightly rounded humeri (Fig. 133D); MEW/HuW = 2.06-2.15. Given these beetles’ large body size, the elytral striae are not deeply impressed, with only the sutural and 2nd striae impressed on the disc, and lateral striae 3-5 indicated by increasingly isolated punctures. Setal formula 2 1(0) 2 0; the lectotype lacks pronotal lateral setae, a second specimen lacks the left seta, with the right present, and the other two examined specimens have both right and left lateral setae present.

Identification

(n = 4). The head is transversely impressed dorsally between the hind eye margins, the constriction visible in dorsal view, and the eyes moderately convex; ocular ratio = 1.54-1.56, ocular lobe ratio = 0.77-0.83. The pronotal lateral margins are subparallel for ~0.13 × pronotal length anterad the obtuse, projected hind angles; median base only sparsely punctate with ~12 small punctures each side. The much reduced microsculpture is distributed as: 1, vertex with obsolete transverse mesh, sculpticell breadth 2 × length; 2, pronotal disc mostly glossy, with obsolete transverse mesh, sculpticell breadth 2 –3× length in places; 3, median base glossy medially, indistinct transverse sculpticells laterally; 4, elytral disc glossy; 5, elytral apex glossy, with patches of indistinct transverse sculpticells. The femoral apex is slightly infuscated, and the basal ¾ of the anterior femoral face is covered with a distinct piceous cloud, leaving a transverse femoral stripe across the apical half.

Male genitalia (n = 1). Aedeagal median lobe large, gracile, distance from parameral articulation to tip 3.7 × depth at midlength (Fig. 138D); apex narrowly expanded, with dorsal projection basad expanded ventral margin producing an oblique apex with rounded ventral tip; the internal sac exhibits both a dorsal and a ventral ostial microtrichial patch (uneverted specimen); flagellar plate elongate, length estimated as 0.5 × parameral articulation-tip distance (uneverted specimen).

Female reproductive tract (n = 1). Bursa copulatrix vase shaped, broader apically, length 1.09 mm, apical breadth 0.50 mm, basal breadth 0.34 mm (Fig. 136C); bursal walls thickly wrinkled; gonocoxite 1 with 4-5 apical fringe setae, a moderate seta at apicomedial angle and 3-4 setae on medial surface (Fig. 137C); gonocoxite 2 subtriangular, apex tightly rounded, lateral margin straight near ensiform setae, base moderately extended laterally, 2 lateral ensiform setae, apical nematiform setae on medial surface at 0.75 × gonocoxite length.

Lectotype.

Male (BPBM) hereby designated, labeled: Thriscothorax ducalis Type D.S. Haleakala Perkins 620 (♂ in pencil) // Type // Hawaiian Is. Perkins 1904-336 // LECTOTYPE Thriscothorax ducalis Sharp J.K. Liebherr (black-margined red label).

Distribution and habitat.

Mecyclothorax ducalis has a distribution restricted to the Waikamoi area in habitats ranging 1210-1525 m elevation (Fig. 139). It was collected during six different collecting dates, starting v-1896 with R.C.L. Perkins, and finishing 14-i-1926 with R.H. Van Zwaluwenberg. None of the collecting events have associated ecological data.