Paratachys perkinsi, Liebherr, 2021

Liebherr, James K., 2021, Hawaiian Paratachys Casey (Coleoptera, Carabidae): small beetles of sodden summits, stony streams, and stygian voids, ZooKeys 1044, pp. 229-268 : 229

Paratachys perkinsi sp. nov. Figures 6B , 7

Tachys arcanicola , Britton 1948: 240 (misidentification).

Type material.

Holotype female (NHMUK): platen mount / 170 on reverse // Hawaiian Is. / R.C.L. Perkins // Kaunakakai / sea level / vii-93 // atomarium (label upside down indicating misidentification) // HOLOTYPE ♀ / Paratachys / Paratachys perkinsi / J. K. Liebherr 2020 (black-margined red label). Britton (1948: 240) lists a second specimen with these data; however, only the single specimen designated holotype above was observed by the author in 1998 (unpubl. data).

Diagnosis.

Distinguished among all Hawaiian Paratachys by the elongate sinuation of the pronotal lateral margins before the right hind angles; the subquadrate, elongate elytra; and the angulate humeral juncture of the basal and marginal elytral grooves (Fig. 6B ). The single known specimen has convex eyes with ten ommatidia crossed by a horizontal diameter of the eye, and 12 ommatidia crossed by a vertical diameter; the OR is 1.26. Elytral interneurs 1 and 2 are continuous on the disc, and interneur 3 is deepest in the basal 1/4 of elytral length and discontinuous on the disc. Standardized body length 2.3 mm.

Description.

Head appearing narrow due to elongate mandibles, mandibular length from dorsal condyle to apex twice distance from condyle to lateroapical angle of labrum; ocular lobes little projected, neck broad, eyes convex but small (Fig. 6B ); frontal grooves bordering convergently convex frons that narrows from anterior supraorbital setae to clypeal margin, the grooves broad and planar laterad convex frons; clypeus convex; labrum transverse, broadly, slightly emarginate apically, six-setose; antennae submoniliform, antennomere 9 length 1.6 × diameter; penultimate maxillary palpomere broadened apically, apical palpomere a narrow spindle (Fig. 6B ). Prothorax slightly transverse, MPW/PL = 1.41, base moderately constricted with lateral margins sinuate well before acute hind angles, MPW/BPW = 1.21; pronotal median base depressed relative to disc, the juncture of disc and base smooth, surface of median base slightly roughened due to minute lenticular longitudinal wrinkles; basal margin trisinuate, medially incurved, laterally slightly oblique, a thin marginal bead posterad laterobasal depressions; depressions deepest along a line running from hind angles parallel to median base-discal margin (Fig. 6B ); pronotal lateral margin beaded, the bead directly adjacent to pronotal disc at midlength; pronotal median impression finely incised, disc convex each side of impression; anterior transverse impression shallow medially, well defined laterally as a narrow groove that extends to moderately projected, tightly rounded front angle. Elytra elongate, broad basally, EL/MEW = 1.57, HuW/MEW = 0.64, lateral margins evenly convex from humeri to subapical sinuation; basal groove evident from fourth interneur, juncture with lateral marginal depression subangulate; lateral marginal depression moderately reflexed, surface translucent, of equal breadth from seta Eo3 to subapical sinuation; disc flat between third interneurs each side; interneurs 1 and 2 deep on disc, slight irregularities along deepest portions, interneur 3 evident anterad and posterad dorsal seta Ed4, the setal impression obscuring interneur near seta. Pterothorax elongate, mesepisternal depression smooth posterad juncture with mesosternum, depression deepest and broadest just dorsad mesocoxal cavity; metepisternum lateral length 2 × maximal width; metathoracic flight wings broad vestigial flaps that extend to position of elytral seta Eo3 (visible in holotype through translucent elytra). Abdomen with two setae each side of apical ventrite in female holotype. Microsculpture evident on all somites; frons covered with evident transversely stretched isodiametric mesh, sculpticells more isodiametric in frontal grooves; pronotal disc with elongate transverse mesh, the surface slightly iridescent due to narrow elongate sculpticells, median base opaque in depressions, surface glossy along elevated ridges; elytra subiridescent due to a mix of transverse-mesh and stretched transverse-mesh microsculpture. Pelage on head, pronotal disc and elytra comprising microsetae separated by distances twice setal length; short microsetae along ommatidial margins of eyes; anterior (ventral) surface of meso- and metathoracic legs bearing pelage of elongate microsetae, the setal bases situated more closely than microsetal lengths. Coloration ferruginous (Fig. 6B ); vertex and frons brunneous, clypeus flavo-brunneous, labrum, mandibles and palpomeres flavous; antennae flavous; pronotal disc and elytra flavo-brunneous, elytral lateral marginal depression slightly paler, elytral epipleuron flavo-brunneous, contrasted to rufo-flavous thoracic and abdominal ventrites; legs flavous from trochanters outward; pro- and mesocoxae concolorous with outer leg segments.

Female reproductive tract.

The single historically collected holotype specimen was not dissected.

Etymology.

This species is named to honor its collector, R.C.L. Perkins, who as a new graduate of Oxford University was sent in 1891 to Hawai‘i, by the British Association for the Advancement of Science to collect zoological specimens in support of the 'Fauna Hawaiiensis’ project ( Sharp 1913; Manning 1986). Dr. Perkins stayed on after his initial Hawaiian surveys, during which the holotype of this species was collected, to serve in the Territory of Hawaii’s Agricultural Department and then as Director of the Experiment Station of the Hawaiian Sugar Planters’ Association ( Scott and Benson 1955; Scott 1956). Throughout his scientific career, Perkins conducted systematic research on a wide variety of insect taxa ( Evenhuis 2005) as well as the control of pestiferous insects and weeds using introduced natural enemies ( Perkins 1897, 1923; Perkins and Swezey 1924).

Distribution and habitat.

The lone specimen representing this species is labelled as Perkins’ lot 170, Kaunakakai, July 1893, sea level. Perkins’ Moloka‘i July collecting commenced on 9 July, however much of his time was spent high in the forests ( Evenhuis 2007). He walked to the coast on 17 July, arriving at Kaunakakai in the afternoon. He spent the next two days hunting shorebirds and coots, and on the 20th "Walked along the coast to Kaluaaha supposed to be about 16 miles E. ... I stayed some time at Kawela ... ( Evenhuis 2007: 262)." After his midday stop at the base of Kawela Gulch he encountered a "heavy shower" and "finishing of the school term" at Kalua 'aha. The next day he walked back to Kaunakakai, and on the 21st came down with a sore throat, which progressed to what he self-diagnosed as "the ‘grippe’ or influenza ( Evenhuis 2007: 163)." He returned to the mountains on 24 July, closing the temporal window during which P. perkinsi could have been collected. Thus, a best guess concerning the collecting locality of the lone Paratachys perkinsi is in the streambed of Kawela Gulch near the coast on 20 July (Fig. 7 ). Such a situation would be similar to the streamside situations frequented by P. terryli of Kauai, although at considerably lower elevation. Kawela Stream at higher elevations houses several flightless riparian species, including the nabid bug, Nabis gagneorum Polhemus (1999), and the very large-bodied, vestigially winged carabid beetle, Blackburnia polhemusi Liebherr ( Liebherr and Zimmerman 2000). The riparian habits of both of these species are unusual among their respective radiations, pointing to Kawela Gulch as a persistent and stable water source able to support populations of flightless insects.

Figures

Figure 6. Paratachys spp., dorsal habitus view A P. arcanicola paralectotype female; Oahu: Honolulu (Bates collection, box 389) B P. perkinsi holotype female; Moloka'i, July 1894 (R. C. L. Perkins lot 170).

Figure 7. Distributional records for Paratachys spp.; P. perkinsi (type locality designated as Kawela Gulch at sea level (•) (see text); P. haleakalae (▪).