Paratachys arcanicola (Blackburn)

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 arcanicola (Blackburn) Figures 3B , 6A

Tachys arcanicola Blackburn, 1878: 158; Sharp 1903: 287; Britton 1948: 240.

Paratachys arcanicola , Erwin, 1974b: 139.

Type material.

Lectotype male (NHMUK), hereby designated: Blackburn two-parallel black line O‘ahu platen ( Zimmerman 1957: 201) with glued, dissected specimen / arcani on reverse // Type (round, red-margined label) // Hawaiian Is. / Rev. T. Blackburn / 1888-30 // Tachys / arcanicola / Blackburn. Type // For / genitalia / See Type Coll. // Lectotype / Tachys / arcanicola / J. K. Liebherr 1998 (black-margined red label). The genitalia slide has left-side labels: Tachys / arcanicola / Blackburn / ♂ Type / E. C. Z. // Lectotype ♂ / Tachys arcanicola / 2020 / J. K. Liebherr (red label glued to E. C. Z. label).

Paralectotypes: Ins. Oahu, Ind. auth. (= Blackburn) (NHMUK, 1); O‘ahu [2-line Blackburn label], Blackburn (NHMUK, 2); Sandwich Is. (Bates collection, box 389), Blackburn (MNHN, 1). The first paralectotype listed above represents a specimen provided by the Rev. T. Blackburn to R.C.L. Perkins for his reference during the 'Fauna Hawaiiensis’ survey.

Non-type material.

Honolulu, Perkins (BPBM, 2).

Diagnosis.

This is a small-bodied species, standardized body length 1.9-2.2 mm, with ovoid elytra; EL/MEW = 1.40. The pronotum is transverse, MPW/PL = 1.43-1.48, dimensions shared among Hawaiian Paratachys only with some individuals of P. aaa (Fig. 9A ), the other small-bodied Hawaiian Paratachys . The pronotal lateral margins are sinuate basally, and much as in P. terryli , subparallel just before the nearly right hind angles. However, known specimens of this species are paler than those of P. terryli (Fig. 1A ), with the flavobrunneous head, pronotum and elytra contrasted less with the flavous legs (Fig. 6A ).

Description.

Head quadrate, ocular lobes little projected, neck broad; 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; eyes small, only slightly convex (Fig. 6A ), size ranging from five to seven ommatidia horizontally, six to nine ommatidia vertically; OR 1.16-1.26 for small-eyed vs. large-eyed individuals; labrum quadrate, apical margin straight, six-setose; antennae submoniliform, antennomere 9 length 1.6 × diameter; penultimate maxillary palpomere broadened apically, apical palpomere a narrow spindle (Fig. 6A ). Prothorax transverse, MPW/PL = 1.43-1.48, base moderately constricted with lateral margins sinuate anterad right hind angles, MPW/BPW = 1.23-1.29; pronotal median base depressed, surface reticulate due to pebbly microsculpture, unmargined; basal margin beaded each side posterad laterobasal depression which is convex medially, the convexity continuous with disc; pronotal lateral margin beaded, depression mesad bead narrow, but broad enough so that a row of sculpticells can be observed lining the groove; pronotal median impression finely incised, disc convex each side of impression, anterior transverse impression shallow, defining a flat anterior collar medially, groove obsolete laterally near tightly rounded, little protruded front angles. Elytra subovoid, lateral margins evenly convex from humeri to apex, maximum width approximately midlength, HuW/MEW = 0.59; basal groove present laterad seta Ed1 (parascutellar seta), groove subangularly joined to lateral marginal depression; lateral marginal depression moderately reflexed, of equal breadth from seta Eo2 to subapical sinuation; elytral interneurs 1 and 2 deep, smooth on disc, interneur visible only as short segment anterad and obsolete very shallow impression posterad dorsal seta Ed4. Pterothorax moderately elongate, mesepisternal depression smooth posterad juncture with mesosternum, depression deepest and broadest just dorsad mesocoxal cavity; metepisternum broad and short, lateral length 1.3 × maximal width; metathoracic flight wings vestigial in six specimens examined, the broad stub extended to just beyond position of elytral seta Eo3. Abdomen with one seta each side of apical ventrite in males, two seta each side of ventrite in females. Microsculpture evident on all somites; frons covered with evident transversely stretched isodiametric mesh; pronotal disc with elongate transverse mesh, the surface slightly iridescent due to narrow elongate sculpticells, median base opaque due to rough isodiametric sculpticells; elytra subiridescent due to a mix of transverse-mesh and stretched transverse-mesh microsculpture; abdominal ventrites covered with elongate transverse sculpticells, the surface glossy. Pelage present on head, prothorax, elytra, pterothorax, abdominal ventrites and legs; pelage on head and pronotal disc, comprising microsetae separated by distances subequal to setal length, as well as along ommatidial margins of the eyes; microsetae spaced slightly farther apart on elytra, with intersetal distances up to twice microsetal length; anterior (ventral) surfaces of meso- and metathoracic legs bearing pelage of elongate microsetae, the setal bases situated more closely than microsetal lengths, trochanters and coxae similarly covered with microsetae. Coloration ferruginous (Fig. 6A ); vertex and frons brunneous, clypeus flavo-brunneous, labrum flavous; antennae flavous; maxillary and labial palps flavous; pronotal disc and elytra flavo-brunneous, elytral lateral marginal depression flavous, 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, metacoxae rufo-flavous to match abdominal ventrites.

Male genitalia.

Aedeagal median lobe nearly straight for much of length, slightly, evenly downturned to the broad, shovel-nosed tip (Fig. 3B ); flagellar complex hemi-ovoid, the scoop-like apical surface only slightly incurved along ventral margin; strap-like right paramere with three apical setae [left paramere lost from dissection].

Distribution and habitat.

The Reverend Thomas Blackburn (1878) noted in his initial description of this species, "Very local, but not rare in some mountainous localities ( Blackburn 1878: 158)." Nonetheless, Britton (1948: 240) noted only three specimens in the Blackburn collection (NHMUK), listing them as found at "1500 ft., under bark." The label data do not confirm the elevation or situation, though Blackburn did write "I spent some portion of time (varying from an hour to an occasional twelve hours) in collecting insects on the eastern side of Oahu, as nearly as possible once a fortnight on the average through the six years I spent on the Hawaiian Islands ( Blackburn 1885: 204)." Such relatively brief forays would have restricted his collecting to the southern Koolau Range, encompassing the hills above Honolulu including Round Top, Tantalus, or perhaps Lanihuli or Konahuanui on a long day. These areas were considerably more accessible at that time due to the absence of human residential developments and the depredations of goats on the native vegetation that opened the forest ( Liebherr and Polhemus 1997). R.C.L. Perkins collected two specimens at Honolulu in the early 20th Century, also very likely found on or near Tantalus, as he frequented that site in a continuing search for rarely collected insects ( Perkins 1906), correctly predicting the extinction of many species found only there (e.g., Liebherr 2009). No specimens have been collected near “Honolulu” since Perkins, and we can surmise that this species is extinct.

Nomenclatural notes.

Erwin (1974b) clarified generic concepts of New World tachyines, assigning species to proper genera, and designating lectotypes to stabilize nomenclature for type series of species deposited among multiple worldwide institutions. He assigned Tachys arcanicola Blackburn to Paratachys Casey and wrote "Lectotype, male, here designated, in NHMUK ( Erwin 1974b: 139)." Previously, Britton (1948: 240) cited three NHMUK Blackburn specimens from Oahu, all males, as representatives of T. arcanicola , although he did not select a lectotype from among them. Later during his 1948-1972 tenure as an honorary associate of The Natural History Museum, London ( Upton 2004), E.C. Zimmerman dissected the male labelled with the round, red-margined “Type” label during his researches on Hawaiian Carabidae , with the dissection described above. The NHMUK round red-margined “Type” labels were used variously to designate specimens prior to World War II, and then all beetle specimens were dispersed to safe haven in Wales, Scotland, and to the west of London prior to the Nazi Blitz of 1940-1941 ( Jones 2013; M.E. Bacchus, pers. comm.). Thus, the labels themselves do not hold nomenclatural value. In 1998, the author examined the three male specimens reported in Britton (1948), and labelled the specimen dissected by Zimmerman and bearing the red-margined “Type” label as lectotype. No other specimen of T. arcanicola bearing an Erwin lectotype label was found among NHMUK material at that time. This absence was affirmed by a recent search of the entire NHMUK tachyine holdings (B. Garner, pers. comm.), again resulting in no Erwin-labelled lectotype specimen for this taxon, though Erwin labels were found on various other specimens representing Neotropical taxa for which lectotypes were designated in Erwin (1974b). More broadly, no Erwin lectotype-labelled specimen was found by the author in the H. W. Bates collection in the MNHN, Paris, although a single specimen in the Bates holdings of the Oberthür Collection is accounted for above as a Parisian paralectotype. Because all three syntype specimens of this species in the British Museum are males, all three were identically accounted for both in Britton (1948) and during the author’s 1998 visit, and no other Erwin-labelled lectotype specimen exists in Bates material in Paris, it is unavoidably concluded that Erwin never labelled a specimen as lectotype for this taxon. Because his published designation specified a male specimen, but there are three male syntype specimens in the NHMUK, Erwin failed to designate a "single name-bearing type specimen" as lectotype (I.C.Z.N. 1999, glossary). As "A lectotype may be designated from syntypes to become the unique bearer of the name of a nominal species-group taxon (I.C.Z.N. 1999, Article 74.1)", his published statement is invalid. In the extremely unlikely circumstance that an Erwin-labelled lectotype specimen would surface from some other venue, unlikely because it cannot be one of the three NHMUK specimens cited by Britton (1948), and its very existence would violate Erwin’s (1974b) statement that his lectotype was designated from a NHMUK male specimen, then the lectotype presently designated above would become invalid. The present lectotype designation is undertaken to eliminate ambiguity with regard to how this species is to be tied to zoological nomenclature, with future rediscovery of an Erwin-labelled lectotype specimen of a Blackburn syntype the only means to validate Erwin’s (1974b) published action.

Figures

Figure 1. Paratachys terryli A-I Kauai: Namolokama Mtn. A, B macrophthalmic, brachypterous female; 23 - v- 2005 lot 01 A dorsal habitus view B mentum and associated mouthparts, ventral view C-I compound eye, lateral view C macropterous female; 23 - v- 2005 lot 1 D brachypterous male; 21 - v- 2005 lot 8 E brachypterous male; 23 - v- 2005 lot 1 F brachypterous female; 23 - v- 2005 lot 1 G brachypterous female; 23 - v- 2005 lot 1 H brachypterous female; 23 - v- 2005 lot 1 I brachypterous female; 21 - v- 2005 lot 1 J Kauai: Upper Kawaikoi Stream at Alakai Swamp Trail, 16 - v- 1971; right metathoracic flight wing of male, vestigial morph (elytron removed); 14 - v- 1991 stop 91 - 26 B.

Figure 3. Paratachys spp., male aedeagus, i. e., median lobe and associated smaller right paramere and larger left paramere (right lateral view) A P. terryli; Kauai: Namolokama Mtn., 23 - v- 2005 (CUIC) B P. arcanicola lectotype slide; " Tachys arcanicola Blackburn Type ♂ E. C. Z. (permanent slide, Euparal?, left paramere missing; NHMUK). " C P. haleakalae; East Maui: Haleakala N. P., Kipahulu Vy., 30 - iv- 1991 (CUIC) D-F P. aaa; Hawai'i I D Puna, Mountain View, Kazumura Cave, 21 - xi- 2018, lot HI 00713 (CUIC) E Kau, Ocean View, Kipuka Kanohina System, 21 - xi- 2017, lot HI 00179 (CUIC) F South Hilo, Kaumana Cave, 19 - iii- 2019, lot HI 00942 (CUIC); disassociated left paramere below, ectal view.

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 9. Paratachys aaa A male, dorsal habitus view; Kau, Kona Mala, 21 - xi- 2017, lot HI 00179 B mentum and associated mouthparts, ventral view, of above male specimen C larger ovoid compound eye of female, lateral view; Mountain View, Kazumura Cave, 21 - xi- 2018, lot HI 00722 D moderately sized ovoid compound eye of male, lateral view; also lot HI 00722 E smaller rounded compound eye of male, lateral view; Kaimu, Burn Cave, 16 - 19 - iii- 1994 F small compound eye of male, lateral view; Kaimu, Burn Cave, 16 - iii- 1994 G stenopterous left metathoracic flight wing of male (elytron removed), dorsal view; Kau, Kona Mala, 21 - xi- 2017, lot HI 00179.