Mecyclothorax perstriatus (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 : 21-24

Taxon classification Animalia Coleoptera Carabidae

(002) Mecyclothorax perstriatus (Sharp) Figs 10B, 11 D–G, 12 B–C, 13B, 14

Thriscothorax perstriatus Sharp 1903: 260.

Mecyclothorax perstriatus , Britton 1948b: 158; Liebherr 2005b: 122.

Oopterus plicaticollis Boisduval, Karsch 1881: 1 (misidentification).

Thriscothorax modestus Sharp, Swezey 1954: 53 (misidentification, Cibotium associate).

Diagnosis.

Individuals of Mecyclothorax perstriatus and Mecyclothorax superstriatus share reduced microsculpture, the pronotal disc glossy with an obsolete transverse mesh visible over portions of the disc (Fig. 10 B–C). However the elytral microsculpture is more developed in this species, being an evident, shallow transverse mesh versus an obsolete transverse mesh on a glossy surface in Mecyclothorax superstriatus . Beetles of both species also have smaller eyes that cover less of the ocular lobe than do those of Mecyclothorax perseveratus , with Mecyclothorax perstriatus exhibiting an ocular lobe ratio = 0.83-0.86. The male genitalia provide certain diagnosis, with the aedeagal median lobe apex of Mecyclothorax perstriatus males extended and downturned (Fig. 11 D–G), versus very short and not at all downturned in Mecyclothorax superstriatus (Fig. 11 H–I). Setal formula 2 1(2) 1 0; only one individual was observed within which the basal pronotal seta was unilaterally present. Standardized body length 3.5-4.6 mm.

Identification

(n = 5). The full description of Mecyclothorax perseveratus serves to describe this species with the exception of characters mentioned in the diagnosis. The eyes are convex; ocular ratio 1.51-1.55. The pronotum is cordate with right to acute hind angles; MPW/BPW = 1.54-1.65. The elytra are narrowly to more broadly ovoid; MEW/HuW = 2.09-2.23.

Male genitalia (n = 20). Aedeagal median lobe gracile but shorter than that of Mecyclothorax perseveratus males, distance from parameral articulation to tip 3.5 –4.3× medial breadth (Fig. 11 D–E, G); median lobe apex shorter than that of Mecyclothorax perseveratus , ventral margin angulate just distad ostial opening in lateral view; median lobe apex moderately curved to the right with tip slightly expanded in ventral view (Fig. 11F); internal sac with evident, short flagellar plate, but without evident microtrichial patches (uneverted specimens).

Female reproductive tract (n = 2). Bursa copulatrix bipartite, apex digitiform and narrower than base at vagina, bursa 0.46 mm long overall, base at vagina 0.42 mm broad, digitiform apical lobe 0.37 mm long, 0.14 mm broad (Fig. 12 B–C); bursal surface membranous, translucent, finely wrinkled; gonocoxite 1 with 3 apical fringe setae, a moderate apicomedial seta at apex of medial surface, 5-6 setae basally on medial surface (Fig. 13B); gonocoxite 2 subacuminate with lateral extension, 2 gracile lateral ensiform setae, apical nematiform setae on medial surface at 0.75 × gonocoxite length.

Lectotype.

Female (BMNH), designated by Liebherr (2005b: 122).

Misidentifications.

Karsch (1881) lists Oopterus plicaticollis Boisduval, with its collecting information recorded under MNHU lot number 60815 as "Olinda, 1, Dr. O. Finsch." The single specimen is Mecyclothorax perstriatus , and so Karsch’s mention of the species represents a misidentification. Documentation of Swezey’s (1954) misidentification of Mecyclothorax perstriatus as Mecyclothorax modestus is supported by: 1, specimens that match his collecting date and host information that are; 2, not attributable to Mecyclothorax cordaticollis , the senior name synonymous below with Mecyclothorax modestus , but instead represent this species.

Distribution and habitat.

The recorded distribution of this species spans the western Waikamoi forests, the Hāna Bogs, upper Kīpahulu Valley, and the Manawainui Planeze (Fig. 14). It is a wet forest species, and has been found in association with ‘ōhi‘a, koa , or 'ōlapa trees, or various ferns; Asplenium , Athyrium ('akolea), Cibotium ( hāpu‘u), or Sadleria ( ‘ama‘u). The beetles are active on vegetation at night, and also may be found by sifting litter. As with Mecyclothorax perseveratus , beetles have been collected from yellow-pan traps set on the ground, implying they active walk over the forest floor.