Mecyclothorax perkinsianus (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 : 224-226

Taxon classification Animalia Coleoptera Carabidae

(092) Mecyclothorax perkinsianus (Sharp) Figs 115C, 116D, 117B, 118B

Metrothorax perkinsianus Sharp 1903: 270.

Mecyclothorax perkinsianus , Britton 1948b: 135.

Diagnosis.

Beetles of this species (Fig. 115C) exhibit a dorsal body surface that is as glossy as that of Mecyclothorax vitreus (Fig. 115 A–B), but the pronotum is much less transverse, MPW/PL = 1.08-1.10, and the lateral pronotal seta is present. The sutural and 2nd stri ae are slightly impressed on the disc in association with a slightly convex interval 2. The elytra are rufobrunneous, with the sutural interval paler, rufous basally and rufoflavous apically. In keeping with the narrow elytral base, the humeri are more proximate than in any other member of the group; MEW/HuW = 2.42-2.53. Setal formula 2 1 2 0. Standardized body length 5.2-5.3 mm.

Identification

(n = 2). The eyes are very convex, ocular ratio = 1.57-1.59, and cover much of the protruded ocular lobe, ocular lobe ratio = 0.91. The pronotal hind angles are slightly obtuse with tightly rounded apex, with the margin behind the angles convex, the basal margin continued in a trisinuate curve. The lateral margins are subparallel for only a short distance anterad the hind angles. The pronotal median base is smooth with ~16-17 large isolated punctures each side. The pronotal anterior transverse impression is shallow but distinct, crossed by some fine, shallow longitudinal wrinkles that extend medially across the anterior callosity. The pronotal lateral marginal depression is extremely narrow, constituted only by the beaded margin adjacent to the pronotal disc. The pronotal apex is broader than the base; APW/BPW = 1.07-1.12. The vertex is glossy, bearing only obsolete microsculpture that is difficult to discern. The pronotal disc and median base are also glossy, with obsolete transverse microsculpture over parts of the discal surface and obsolete transverse sculpticells in the laterobasal depression. The elytral disc is glossy with an obsolete, elongate transverse mesh; patches of indistinct isodiametric sculpticells on the elytral apex.

Male genitalia (n = 1). Aedeagal median lobe parallel sided along shaft, moderately robust, distance from parameral articulation to tip 3.8 × depth at midlength (Fig. 116D); apex expanded dorsally a blunt projection, ventrally as acutely rounded tooth, the apical face between slightly convex; internal sac with dorsal ostial microtrichial patch near base, distinct, round ventral ostial microtrichial patch at 1/3 sac length; flagellar plate very large, robust, length 0.67 × parameral articulation-tip distance.

Female reproductive tract (n = 1). Bursa copulatrix columnar, thin and elongate with apical expansion, length 1.42 mm, apical breadth 0.46 mm, midlength breadth 0.32 mm (Fig. 117B); bursal walls thickly wrinkled, base more translucent; gonocoxite 1 with 4 apical fringe setae, a thicker seta basad medioapical angle and 7-10 smaller setae along medial surface (Fig. 118B); gonocoxite 2 broad basally, with lateral margin straight near lateral ensiform setae, apex subacuminate, base broadly extended with curved terminus, 2 broad and elongate lateral ensiform setae, apical nematiform setae on medioventral surface at 0.76 × gonocoxite length.

Lectotype.

Male (BMNH) hereby designated, labeled: Metrothorax perkinsianus Type D.S. Haleakala Perkins 1902 // Type // LECTOTYPE Metrothorax perkinsianus Sharp J.K. Liebherr 1998 (black-margined red label). Sharp (1903: 271) states "This species was discovered by the naturalist to whom we are indebted for Atelothorax optatus ." Under Atelothorax optatus , junior synonym of Mecyclothorax cognatus , Sharp writes: "The unique exponent was found on Haleakala last year by a friend of Mr. Perkins. I regret that I do not know the name (1903: 269)." Sharp (1896, 1903) did know and write about Dr. Albert Koebele and Brother Matthias Newell of Wailuku, Maui, but he did not mention George C. Munro, the noted ornithologist who emigrated to Hawai‘i in 1890 to collect birds with Henry C. Palmer for Lord Walter Rothschild ( Amadon 1964). Munro provided specimens to Perkins; e.g., the types of Mecyclothorax munroi ( Perkins 1937), junior synonym of Mecyclothorax karschi Blackburn ( Liebherr 2011), and Blackburnia munroi ( Perkins 1936). Specimens of Mecyclothorax planatus and Mecyclothorax cognatus included in this revision were collected in 1936 at Olinda by Munro. These later specimens do not prove that Munro was the “naturalist” in question who was the only person to see Mecyclothorax perkinsianus in nature, but Munro would have favored the Waikamoi collecting area-the range of Mecyclothorax cognatus (Fig. 31)-as it has always been well known for its native birds.

Distribution and habitat.

Mecyclothorax perkinsianus is the only Haleakalā Mecyclothorax species for which we have no authoritative locality information. Based on the forest habitats available to entomologists at the turn of the 20th Century, bolstered by the best guess of G.C. Munro as the collector, the Waikamoi forest at 1300 m elevation seems the most likely collecting site, and so is designated the type locality.