Mecyclothorax scarites, 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 : 190-192

Taxon classification Animalia Coleoptera Carabidae

(079) Mecyclothorax scarites sp. n. Figs 95D, 96 D–E, 97C, 98C, 99

Metrothorax perkinsianus Sharp, Swezey 1954: 53 (misidentification, Cibotium associate).

Diagnosis.

This species (Fig. 95D) is assigned to the setal formula 1 0 2 0 along with two other Haleakalā species- Mecyclothorax molops (Fig. 95A) and Mecyclothorax macrops (Fig. 95B)-yet it is more similar in pronotal configuration, overall body proportions, and elytral striation to Mecyclothorax scaritoides (Fig. 95C), a species characterized by presence of both supraorbital setae. In addition to the supraorbital setae, Mecyclothorax scarites can be distinguished from Mecyclothorax scaritoides by the shallow but distinct transverse microsculpture on the elytral disc that is composed of sculpticells 3 –4× broad as long plus transverse lines not joined into a mesh. The discal elytral striae are not punctate, with the sutural stria irregularly impressed along its discal portion, and striae 2-4 variable impressed among individuals, but smooth to slightly irregular across the disc in all individuals. The elytra are slightly more ovoid than those of Mecyclothorax scaritoides , with the humeral angles more distant relative to overall elytral width; MEW/HuW = 1.93-2.0. Standardized body length 5.3-5.5 mm.

Description

(n = 5). Head capsule with frontal grooves broad, sinuous, a broad lateral convexity before eye, groove nearly joined to postocular groove anterad posterior supraorbital seta; dorsal impression of neck slightly concave; eyes moderately convex, covering much of ocular lobe, ocular ratio = 1.47-1.52, ocular lobe ratio = 0.84-0.88; labral anterior margin very shallowly emarginate medially; antennae filiform, antennomeres 1-3 glabrous; mentum tooth with sides acute, apex tightly rounded. Pronotum moderately transverse, MPW/PL = 1.20-1.22, base moderately constricted, MPW/BPW = 1.47-1.55, lateral margin sinuate for 0.1 × pronotal length anterad obtuse hind angles, their apex rounded; median base coplanar with disc medially, ~14 small, isolated punctures each side; basal margin moderately convex between hind angles; median longitudinal impression very shallowly incised, traceable to obsolete; anterior transverse impression broad, shallow medially, narrow and finely incised laterally; anterior callosity slightly convex, smooth; front angles slightly projected, tightly rounded; pronotal apical and basal widths subequal, APW/BPW = 0.94-1.05; lateral marginal depression very narrow, edge beaded even at front angle, disc very convex; laterobasal depression smooth, convex with U-shaped groove along lateral and basal margins of convexity. Proepisternum with 5 minute punctures along hind marginal groove; prosternal process with very shallow depression medially. Elytra ovoid, greatest width slightly behind midlength; disc very convex, slightly depressed along suture, sides distinctly sloped to near vertical inside marginal depression; basal groove distinctly curved to subangulate humerus; parascutellar seta present; parascutellar striole shallow, with 3-4 elongate punctures, smooth between punctures; sutural interval slightly more convex than intervals 2-4 throughout their length; sutural stria narrow, moderately deep apically, 2nd stria obsolete, traceable at apex; 8th interval laterad 7th stria of similar convexity to fused apical portion of striae 5 + 7; 2 dorsal elytral setae at 0.19 –0.23× and 0.52 –0.53× elytral length, setal impressions very small, crossing 1/3 of interval 3; lateral elytral setae arranged in anterior series of 7 setae and posterior series of 6 setae; elytral marginal depression very narrow throughout, a low bead present at humerus, a more distinct bead near subapical sinuation; subapical sinuation very shallow, less concave than width of marginal bead. Mesepisternum with ~10 punctures in 2-3 rows; metepisternal width to length ratio = 0.73; metepisternum/metepimeron suture distinct. Abdomen with irregular lateral wrinkles on ventrites 1-6, lateral depressions on ventrites 3-6; suture between ventrites 2 and 3 effaced; apical male ventrite with 2 marginal setae and apical female ventrite with 4 equally spaced setae plus median trapezoid of 4 subequal, short setae. Legs-metatarsomere 1/metatibial length ratio = 0.20; metatarsomere 4 length along outer lobe 1.5 × medial tarsomere length, apical and subapical setae present, the lateral subapical seta short; metatarsal dorsolateral sulci broad, shallow, medially subcarinate on metatarsomere 1 only. Microsculpture of vertex obsolete transverse mesh, sculpticell breadth 2 × length, surface glossy; pronotal disc with obsolete transverse mesh, sculpticell breadth 3 –4× length, most parts glossy, median base glossy, indistinct transverse cells laterally; elytral apex with shallow transverse mesh, sculpticell breadth 2 –3× length; metasternum with obsolete transverse mesh, glossy; laterobasal abdominal ventrites with swirling isodiametric and transverse microsculpture. Coloration of vertex rufous with a piceous cast; antennomeres 1-3 rufoflavous, 4-11 rufobrunneous; pronotal disc rufous, concolorous basally and later ally, apex slightly paler; proepipleuron pale rufobrunneous, proepisternum rufobrunneous; elytral disc rufous, sutural interval concolorous basally, rufoflavous apically; elytral marginal depression and 9th interval rufoflavous apically; elytral epipleuron pale rufobrunneous, metepisternum rufobrunneous; abdomen rufobrunneous, ventrites 1-3 rufoflavous laterally, apical 1/6 of apical ventrite flavous; metafemur rufoflavous; metatibia rufoflavous with brunneous cast.

Male genitalia (n = 2). Aedeagal median lobe slender, distance from parameral articulation to tip 5.0 × depth at midlength (Fig. 96D); apex distinctly expanded dorsally and broadly expanded ventrally producing an apical knob, the outline of the tip broadly rounded; internal sac elongate, sac length from ventral margin of ostial opening to base of flagellar plate 0.78 × parameral articulation-tip distance, without ornamentation (Fig. 96E); flagellar plate very short, nearly as broad as long, length 0.24 × parameral articulation-tip distance.

Female reproductive tract (n = 1). Bursa copulatrix columnar with narrower apex, broader base, length 0.91 mm, apical breadth 0.23 mm, basal breadth 0.41 mm (Fig. 97C); bursal walls translucent, thinly wrinkled; gonocoxite 1 with 3-4 apical fringe setae (Fig. 98C), a thick, curved seta at medioapical angle and 10-11 smaller setae along medial surface; gonocoxite 2 falcate with acuminate tip, base broadly extended laterally with curved terminus, 2 broad lateral ensiform setae, apical nematiform setae on medioventral surface at 0.66 × gonocoxite length.

Holotype.

Male (BPBM) dissected and labeled: Kula Pipe / Line, Maui / 4200 ft. / Jan. 14, 1926 // R H VanZwal- / uwenburg // blue square // Mecyclothorax / scarites / ♂ #2 / det. J.K. Liebherr 2014 // 1 // HOLOTYPE / Mecyclothorax / scarites / Liebherr / det. J.K. Liebherr 2015 (black-margined red label).

Paratypes.

HI: Maui, Haleakala, Olinda, Rubus , 1280 m el., 27-ii-1926, Swezey (BPBM, 1), Cheirodendron , 1280 m el., 27-ii-1926, Swezey (BPBM, 1), Acacia koa , 1280 m el., 10-x-1926, Swezey (BPBM, 1; CUIC, 1); Koolau For. Res., Kula Pipeline Rd., Cibotium menziesii , 975-1210 m el., 27-ii-1935, Swezey (BPBM, 1).

Etymology.

The cylindrical body shape of Mecyclothorax scaritoides appears to be the basis for Blackburn (1878b) using a species epithet derived from the Greek skaritis, that stem used by Fabricius (1775) to name the large-bodied Scarites beetles of the Holarctic. This species is given the species epithet scarites to complete the cycle with the generic name Scarites F.

Distribution and habitat.

Mecyclothorax scarites is known from two localities peripheral to the known localities of Mecyclothorax scaritoides (Fig. 99) in the leeward forests uphill (mauka) from Olinda. Based on the careful ecological labeling of specimens by O.H. Swezey, this species is known to have occurred on koa , Cheirodendron ('ōlapa), Cibotium menziesii ( hāpu‘u), and Rubus ( ‘ākala). Mecyclothorax scarites is closely related yet clearly distinct from Mecyclothorax scaritoides . The two species were parapatrically distributed, with Mecyclothorax scarites appearing in the collecting record subsequent to the last appearance of any specimen of Mecyclothorax scaritoides . Their patchwork appearances in the scientific record are consistent with a haphazard pattern of habitat destruction along the leeward edge of the 19th Century Koa- ‘Ōhi‘a Mesic Forest.