Mecyclothorax pirihao, Liebherr, James K., 2012

Liebherr, James K., 2012, New Mecyclothorax spp. (Coleoptera, Carabidae, Moriomorphini) define Mont Mauru, eastern Tahiti Nui, as a distinct area of endemism, ZooKeys 227, pp. 63-99 : 80-83

6. Mecyclothorax pirihao sp. n. Figs 4C5 D–E 6C7C

Diagnosis.

This species and Mecyclothorax spinosus Perrault share the characteristics of: 1, two supraorbital setae and two dorsal elytral setae, therefore a setal formula of 2121; 2, deep, smooth and complete elytral striae 1-8; 3, regular transverse-mesh elytral microsculpture and feeble transverse microsculpture on the pronotal disc; and 4, sparsely punctate pronotal median base, the punctures small and separated by glossy areas with indistinct microsculpture. However the species can be easily distinguished by the pronotal hind angles, which are obtuse-rounded in this species (Fig. 4C) versus acute and distinctly projected in Mecyclothorax spinosus ( Perrault 1989: fig. 22). The pronotal median base is also narrower in this species, MPW/BPW = 1.83-1.90 (n = 5), versus 1.59 -1.63 (n = 2) in Mecyclothorax spinosus . The male aedeagal median lobe apex is also dramatically different: downturned with a slight ventral projection in this species (Figs 5D-E), versus dorsally spinose in Mecyclothorax spinosus ( Perrault 1989: fig. 13). Finally, individuals of this species are larger; standardized body length 4.2-5.0 mm, versus 4.1 mm for Mecyclothorax spinosus .

Description.

Head capsule with slightly convergentfrontal grooves, triangularly depressed posterad frontoclypeal suture, the apex directed medially onto frons, terminated narrowly mesad thin carina immediately inside dorsal supraorbital seta, frons crossed by numerous fine transverse wrinkles emenating from groove; frons and vertex convex medially, neck not depressed; ocular lobe moderately protruded, joined to gena at broad, shallow groove; ocular ratio 1.47-1.51, ocular lobe ratio 0.81-0.89; labral anterior margin angularly emarginated medially ⅛ × length; antennomeres 1-3 glabrous except for apical setae, minute pore sensilla visible across surface; antennae elongate filiform, eighth segment length 2.25 × maximal breadth; mentum tooth sides defining acute angle, apex rounded. Pronotum extremely constricted basally, moderately transverse, MPW/PL = 1.17-1.25 (n = 5); lateral margin slightly to distinctly sinuate anterad obtuse, rounded, glabrous hind angle; median base moderately depressed relative to disc, margin with disc lined with 4-5 small, circular punctures, 12-13 smaller punctures posteriorly across each side of base; basal margin slightly convex between laterobasal depressions, margin posterad depression slightly expanded posteriorly inside hind angle; median longitudinal impression finely incised, shallow, present as lenticular depression at front of median base; anterior transverse impression broad, shallow, unmargined anteriorly in middle of disc, finely incised in outer half of breadth each side; anterior callosity slightly convex, depressed relative to disc, crossed with fine longitudinal wrinkles; front angles slightly protruded, rounded; distance between front angles visibly greater than basal width, APW/BPW = 1.10-1.20 (n = 5); lateral marginal depression very narrow at midlength, slightly wider at front angle, bead broader along sinuate basolateral margin; laterobasal depression narrow, sinuously defined laterally by broadened marginal bead, medially by punctate edge of median base; proepisternum with 5-6 distinct punctures along hind margin, about 5 punctures along hind margin of proepimeron; prosternal process broadly margined laterally, narrowly depressed medially between procoxae. Elytra oblong, sides subparallel at midlength, disc flat near suture; basal groove well developed, curved anterolaterally to angulate humerus; humeri proximate, MEW/HuW = 2.42-2.56 (n = 5); parascutellar seta present, situated in middle of sutural stria; parascutellar striole 4-5-punctate, continuous; sutural interval and lateral intervals of similar convexity basally, sutural interval narrower and convexly upraised to meet at suture apically; all striae evident in basal half, striae 1-6 moderately deep, minutely punctate at strial depth, stria 7 shallower but complete, nearly smooth; all striae complete at apex, sutural stria deep and fine, stria 7 deep and broad, the eighth interval convexly subcarinate apicad the subapical sinuation; dorsal elytral setae in evident depressions that cross half to the entire width of interval 3, setae positioned at 0.21 –0.24× and 0.54 –0.59× elytral length; apical elytral seta present, subapical seta absent in most individuals, rarely present unilaterally; lateral elytral setae 7 + 6; elytral marginal depression narrow at humerus but margin upraised, margin upraised laterally, more beadlike as depression narrows to subapical sinuation; subapical sinuation very shallow, elytral margin straight. Mesepisternum with 11 punctures in 1-2 vertical rows; metepisternum elongate, width to length ratio 0.68; metepisternum separated from metepimeron by distinct suture; metathoracic flight wing a triangular flap with inner and posterior margins of equal length, apex of longer lateral margin extended 0.8 × distance to hind margin of metanotum; rudiments of R and M veins visible, not melanic, the same coloration as vestigium membrane. Abdomen with visible ventrites 1 -5 irregularly wrinkled laterally, ventrites 3-6 with round depressions laterally; suture between visible ventrites 2 and 3 effaced laterally. Legs gracile, metatarsomere 1 length 0.24 × metatibial length; metatarsomere 4 emarginated apically, overall length 1.4 × median tarsomere length; metatarsomere 4 with apical and subapical setae; metatarsal dorsolateral sulci broad and shallow, tarsomere dorsal surface medially subcarinate. Microsculpture of head an indistinct transverse mesh, sculpticell breadth 2 –3× length, sculpticells most visible just outside area of reflected light; pronotal disc with transverse mesh, sculpticell breadth 3 –4× length, mixed with glossy patches; pronotal median base glossy, indistinct isodiametric sculpticells visible along edge of reflected light; elytral disc with regular transverse mesh, sculpticell breadth 3 –5× length; elytral apex with shallow transverse mesh, sculpticell breadth 2 –4× length; metasternum glossy, elongate transverse mesh visible in part; laterobasal abdominal ventrites with shallow, swirling isodiametric and transverse sculpticells. Coloration of head rufobrunneous, piceous cast in frontal grooves, clypeus rufoflavous; antennomere 1 flavous, antennomeres 2-11 rufoflavous; pronotal disc brunneous, margins slightly paler; proepipleuron rufoflavous, proepisternum rufobrunneous; elytral disc brunneous wih silvery metallic reflection; sutural interval pale rufous basally, rufoflavous apically; elytral margin concolorous with disc at humerus, deepest part of lateral depression rufoflavous in apical half; elytral epipleuron rufoflavous, metepisternum rufobrunneous; visible abdominal ventrites 1-3 rufobrunneous, ventrites 4-6 rufoflavous; apical half of apical abdominal ventrite flavous; metafemur flavous with brunneous cast; metatibia flavous, carina associated with longitudinal setal series darker, brunneous.

Male genitalia. (n = 2). Aedeagal median lobe evenly curved and of subequal diameter from basal bulb to ostial opening, apex with rounded dorsal projection at base, the downturned tip rounded to tightly rounded (Figs 5D, E); median lobe straight in euventral view; internal sac with broad ventral microtrichial field but without spicules; flagellar plate of moderate size, length 0.35 × distance from parameral articulation to distal face of apex; parameres extended 0.83 × distance from parameral articulation to apex.

Female reproductive tract. (n = 1). Bursa copulatrix shape columnar, length 2.5 × maximal breadth compressed on microslide (Fig. 6C), membranous surface wrinkled and unevenly stained with Chlorazol Black; spermatheca obovate, broadest near apex, reservoir about 0.25 × length of spermathecal duct that enters dorsal wall of bursa dorsad the basally broad common oviduct; membranous ramus mesad basal gonocoxite 1 very long, extended as a fold in dorsal vagina wall to apex of basal gonocoxite 1 (Figs 6C, 7C); basal gonocoxite 1 with 4 apical fringe setae along middle of coxite apex, plus 3 smaller setae near apicomedial angle (Fig. 7C); 2-3 very small setae in medial half of basal gonocoxite; apical gonocoxite 2 broad basally, base broadly extended laterally, with 2 subequal lateral ensiform setae, 1 narrower dorsal ensiform seta, and 2 moderately elongate apical nematiform seta.

Holotype male (MNHN) labeled: French Polynesia: Tahiti Nui / Mt. Mauru trail nr. pylon 3 / el. 1010 m 5-IX-2006 lot 03 / 17°38.094'S, 149°22.073'W / beating Blechnum fern / fronds J.K. Liebherr // HOLOTYPE / Mecyclothorax / pirihao / J.K. Liebherr 2012 (black-bordered red label).

Allotype female (MNHN) labeled as holotype except for allotype designation.

Other paratypes.

SOCIETY ISLANDS: Tahiti Nui; Mauru, pylon 3 to 4, 1010 m el., 17°38.08'S, 149°22.07'W, beating Blechnum fern, 05-ix-2006 lot 03, Liebherr (CUIC, 1), pyrethrin fog Dicranopteris / Blechnum , 06-ix-2006 lot 01, Liebherr (CUIC, 2; NMNH 1); pylon trail, 960-1010 m el., 17°38.08'S, 149°22.07'W, beating ferns, 06-ix-2006 lot 02, Liebherr (CUIC, 3; NMNH, 1); 880-960 m el., 17°38.05'S, 149°21.66'W, beating ferns, 06-ix-2006 lot 03, Liebherr (CUIC, 2); above pylon 4, cloud forest, 1100-1110 m el., 17°37.90'S, 149°22.34'W, beating Weinmannia / Myrsine / Melicope , 20-ix-2006 lot 01, Liebherr (CUIC, 2), 1080 m el., 17°37.92'S, 149°22.32'W, pyrethrin fog fern frond tangles, 20-ix-2006 lot 02, Liebherr (CUIC, 1), 20-ix-2006 lot 03, Ewing (EMEC, 6).

Etymology.

The Tahitian word pirihao, meaning narrow, constricted, or close ( Wahlroos 2002), is used to signify the basally constricted pronotum characterizing this species. As Tahitian, the species epithet pirihao is to be used as a noun in apposition.

Distribution and habitat.

This is the most commonly encountered, and most broadly distributed species within the elevational range so far sampled on Mauru, having been collected in habitats at 880-1110 m elevation. However, 20 of the 22 specimens were collected in association with ferns of either the genus Blechnum or Dicranopteris , and only 2 were associated with flowering plants; a mixed beating sample from Weinmannia , Myrsine , and Melicope .