Mecyclothorax crassuloides, Liebherr, James K., 2015

Liebherr, James K., 2015, The Mecyclothorax beetles (Coleoptera, Carabidae, Moriomorphini) of Haleakala-, Maui: Keystone of a hyperdiverse Hawaiian radiation, ZooKeys 544, pp. 1-407 : 195-197

Taxon classification Animalia Coleoptera Carabidae

(081) Mecyclothorax crassuloides sp. n. Figs 96 G–I, 97D, 98D, 100B, 101

Diagnosis.

This species (Fig. 100B) and Mecyclothorax crassulus (Fig. 100C) are cryptic, sibling species, and based on synapomorphous configurations of the male aedeagal median lobes (Fig. 96 G–J), they are sister species. They can be diagnosed externally by microsculpture only, with this species characterized by the elytra bearing indistinct isodiametric sculpticells in transverse rows on the disc, those sculpticells visible only outside any areas of reflected microscope light. On the elytral apex, the isodiametric sculpticells are more visible, but they are flat without upraised centers. The male aedeagal median lobe is much more robust in this species, broader dorsoventrally with a broader apex (Fig. 96I). The aedeagal internal sac is also larger, in keeping with the lobe dimensions, and more heavily spiculated. Setal formula 2 1 2 0. Standardized body length 4.5-5.1 mm.

Description

(n = 5). Head capsule with frontal grooves moderately deep, broad, the convexity laterad groove broad and low, groove terminated at short carina mesad anterior supraorbital seta; dorsal impression of neck slightly concave; eyes convex, ocular ratio = 1.54-1.58, moderately large, ocular lobe ratio = 0.74-0.80; labral anterior margin angularly emarginate 1/8 length; antennae filiform, antennomeres 2-3 with sparse pelage of short setae; mentum tooth with sides acute, apex tightly rounded. Pronotum moderately transverse, MPW/PL = 1.20-1.30, distinctly constricted basally, MPW/BPW = 1.67-1.80; hind angle acute, lateral margin subparallel for 0.1 × pronotal length; median base depressed relative to disc, ~13 small, isolated punctures each side; basal margin straight, extended posteriorly near hind angles; median longitudinal impression very finely incised, within slight depression of disc, crossed by indistinct transverse wrinkles; anterior transverse impression broad, deep, may be crossed by distinct longitudinal wrinkles; anterior callosity slightly convex, smooth or with minute longitudinal wrinkles; front angles slightly produced, tightly rounded; apical pronotal width much greater than basal width, APW/BPW = 1.12-1.20; lateral marginal depression narrow, edge upturned, slightly broader at front angle; laterobasal depression with slightly irregular surface as on median base, continuous with lateral depression. Proepisternum with 5 minute punctures along hind marginal groove; prosternal process narrowly, evenly depressed medially. Elytra distinctly ovoid, widest behind midlength; disc slightly depressed along suture, sides distinctly sloped to marginal depression; basal groove briefly curved to subangulate humerus, the humeral angles proximate relative to elytral width, MEW/HuW = 2.31-2.43; parascutellar seta present; parascutellar striole brief, with 3-4 punctures, deep, continuous between punctures; sutural interval convex throughout length, disc depressed each side at sutural stria; discal striae 2-4 obsolete, partially traceable by very small punctulae or by cuticular pigment dots associate with strial development, lateral striae 5-7 absent (again their course visible only by serial dots of pigment associated with strial development); both 8th interval laterad 7th stria and fused apical portion of striae 5 + 7 slightly, broadly convex; 2 dorsal elytral setae at 0.26 × and 0.54 –0.65× elytral length, setal impressions very small, shallow, spanning ¼ of interval 3; lateral elytral setae arranged in anterior series of 7 setae and posterior series of 6 setae; elytral marginal depression broadest outside humerus, margin upturned in basal half, beaded near subapical sinuation; subapical sinuation shallow, more abruptly incurved anteriorly. Mesepisternum with ~10 large punctures in 2-3 rows; metepisternal width to length ratio = 0.63; metepisternum/metepimeron suture distinct. Abdomen with irregular lateral wrinkles on ventrites 1-5, lateral depressions on ventrites 3-6; suture between ventrites 2 and 3 partially effaced; apical male ventrite with 2 marginal setae and apical female ventrite with 4 equally spaced setae and median trapezoid of 4 subequal, short setae. Legs-metatarsomere 1/metatibial length ratio = 0.20; metatarsomere 4 length along outer lobe 1.3 × medial tarsomere length, apical and subapical setae present; metatarsal dorsolateral sulci broad, shallow, basal tarsomere medially subcarinate. Microsculpture of vertex a transverse mesh, sculpticell breadth 2 –3× length; pronotal disc with shallow transverse mesh to transverse lines, glossy in part, median base glossy with indistinct transverse sculpticells laterally; metasternum with transverse mesh; laterobasal abdominal ventrites with swirling isodiametric and transverse microsculpture. Coloration of vertex rufous with a piceous cast; antennomere 1 rufoflavous, 2-11 rufobrunneous in fully melanized individuals, antennomeres 1-3 rufoflavous in less melanized beetles; pronotal disc rufous, lateral margins concolorous, base and apex rufopiceous; proepipleuron rufoflavous, proepisternum rufoflavous dorsally, rufobrunneous ventrally; elytral disc rufous with a dark brunneous cast, sutural interval rufous basally, rufoflavous apically; elytral interval 9 rufopiceous, marginal depression rufoflavous; elytral apex rufoflavous only on interval 8 and along apical margin; elytral epipleuron flavous, metepisternum rufoflavous; abdomen rufoflavous; metafemur flavous with smoky brunneous apex; metatibia rufobrunneous with piceous cast.

Male genitalia (n = 2). Aedeagal median lobe very broad basally, attenuated apically with sinuous ventral surface, distance from parameral articulation to tip 2.4 × basal depth (Fig. 96G, I), apex thick at distal end of ostial opening, sinuously narrowed to acutely pointed tip; base of median lobe nearly symmetrical in ventral outline (Fig. 96H) but left margin broadly curved 90° rightward before bluntly rounded tip in this view; internal sac with broadly convex dorsal lobe near base of sac, a suggested dorsal ostial microtrichial patch on right side at base, and ventral surface broadly covered with dark macro- and microspicules (Fig. 96I); flagellar plate elongate, length 0.50 × parameral articulation-tip distance.

Female reproductive tract (n = 1). Bursa copulatrix columnar with rounded apex, broader base, length 1.0 mm, apical breadth 0.39 mm, basal breadth 0.48 mm (Fig. 97D); bursal walls translucent with shagreened surface and very fine wrinkles; gonocoxite 1 with 2-4 apical fringe setae, a thick, curved seta at medioapical angle and 6-8 smaller setae along medial surface (Fig. 98D); gonocoxite 2 subtriangular with subacuminate tip, 2 lateral ensiform setae, apical nematiform setae on medioventral surface at 0.78 × gonocoxite length.

Holotype.

Female (CUIC) labeled: HI: Maui Haleakala N.P. / Kipahulu Vy. Central / Pali Tr. 1200 m el. / 29-IV-1991 sifting / moss & leaf litter // J.K. Liebherr / A.C. Medeiros, / Jr. collectors // HOLOTYPE / Mecyclothorax / crassuloides / Liebherr / det. J.K. Liebherr 2015 (black-margined red label).

Paratypes.

HI: Haleakala N.P., Northeast Rift, Midcamp Bog Cabin, sift Metrosideros humus, 1665 m el., 18-v-1993 lot 01, Liebherr/Medeiros (CUIC, 1), lot 05 Liebherr/Medeiros (CUIC, 1), New Greensword Bog, sift Metrosideros humus, 1850 m el., 17-v-1993 lot 05, Liebherr/Medeiros (CUIC, 1); Hana For. Res., Horseshoe Bog nr. Haleakala N.P., Cheirodendron / Clermontia , 1810 m el., 11-v-1998 lot 05, Ewing (CUIC, 1), Upper Hana, [= nr. Heleleikeoha State Fence Camp], 1730 m el., 14-xi-1973, Whittle (BPBM, 1); Koolau For. Res., Hanawi N.A.R., Kuhiwa Vy. E rim, pyrethrin fog Metrosideros , 880 m el., 09-vi-1999 lot 06, Polhemus (NMNH, 1), lot 09 Polhemus (NMNH, 1), pyrethrin fog steep streambank, 880 m el., 10-vi-1999 lot 01, Polhemus (NMNH, 1), Poouli Cabin, beat vegetation, 1590 m el., 05-v-1998 lot 04, Ewing (CUIC, 1), pyrethrin fog Metrosideros /moss, 1590 m el., 05-v-1998 lot 01, Liebherr (CUIC, 1).

Etymology.

The adjectival species epithet crassuloides is derived from the Latin crassus ; thick, heavy ( Jaeger 1955). This species and Mecyclothorax crassulus below are named to follow Mecyclothorax crassus of West Maui ( Sharp 1903), a closely related species. As crassulus is the diminutive of crassus , then the epithet crassuloides used here means resembling a diminutive crassus .

Distribution and habitat.

Mecyclothorax crassuloides is distributed from Hanawī through the Hāna Bogs to Kīpahulu Valley (Fig. 101). It is known from 880-1590 m elevation in Kuhiwa Valley, and at 1200 m elevation within Kīpahulu Valley. The bog localities range in elevation 1665-1850 m. It has been collected in leaf litter, humus, and moss associated with ‘ōhi‘a, as well as associated with Cheirodendron ('ōlapa), Clermontia (oha), and Leptecophylla (pūkiawe). The 11 separate collecting events of this species have each included only single specimens; unusual among Haleakalā Mecyclothorax spp.