Paratachys Casey, 1918

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 Casey, 1918

Paratachys Casey, 1918: 174 (type species Paratachys austinicus Casey by original designation); Erwin 1974b: 128; Boyd and Erwin 2016: 95, 110.

Eotachys Jeannel, 1941: 426 (type species Tachys bistriatus Duftschmid by original designation). Synonymy by Erwin (1971: 236).

Macrotachys Kult, 1961: 2 [junior homonym of Macrotachys Uéno, 1953: 42] (type species Bembidium fulvicolle Dejean by original designation). Synonymy under Eotachys by Lindroth (1966: 431).

Diagnosis.

These beetles can be diagnosed by: deep paramedial pits of the mentum (Figs 1B , 8B , 9B ); head with two supraorbital setae each side (Figs 1C, D , 8C, D , 9D, F ); pronotum moderately cordate to nearly quadrate, MPW/BPW = 1.17-1.34; anterior terminus of elytral apical recurrent groove (ARG) slightly to distinctly hooked and situated laterad position of interneur 4, ARG laterally encompassing the fourth discal seta Ed5-6 (Figs 1A , 6 , 8A , 9A ); elytral setation including ombilicate setae in an anterior series Eo1-4, a posterior series Eo5-8 associated with posterior sulcus, and Eo9 just mesad ARG, plus dorsal setae Ed1, Ed5-6, Ed7, and Ed8; interneur 8 with posterior sulcus in apical half of elytron, the anterior portion of sulcus directed away from the elytral lateral margin and encompassing setae Eo5-6, and setae Eo7 and Eo8 situated toward the elytral apex between i8 and the apical recurrent groove; and protibia expanded laterally at apical 1/4 of length (Fig. 1A ), the associated latero-apical notch lined basally with a transverse row of closely spaced setae (e.g., Maddison et al. 2019: fig. 7A).

For Hawaiian taxa the position of the dorsal seta within the arcuate ARG differs from that in Neotropical Paratachys ( Boyd and Erwin 2016) by being situated near the middle of the arc (Figs 1A , 8A , 9A ), not further forward near the apical hooked terminus of the groove (e.g., Boyd and Erwin 2016: fig. 1A, C). This suggests that the seta within the arc may represent Ed6 in Hawaiian Paratachys , vs. Ed5 in Neotropical taxa ( Boyd and Erwin 2016: fig. 1A). An anterior placement of the seta mesad the hooked terminus of the ARG is also observed in Asian Paratachys ( Andrewes 1925: plate 3; Tanaka 1956: fig. 1; Tanaka 1960: fig. 1; Habu 1977: fig. 1; Baehr 2017: figs 29-34), the Palaearctic P. bistriatus (Duftschmid) ( Jeannel 1941: fig. 168A) as well as numerous other Palaearctic species ( Coulon 2004: figs 2-4), various Madagascan species ( Jeannel 1946: fig. 154), Canary Island species ( Machado 1992: fig. 73C, D), and Nearctic taxa such as P. proximus (Say) and P. scitulus (LeConte) ( Lindroth 1966: figs 209f, 222).

Finally, all Hawaiian species have the cuticular surfaces of head, prothorax, elytra, meso- and metathoracic sternites, abdominal ventrites, and femora covered with a pelage of fine microsetae (Figs 1C-I , 8C, D , 9C-F ). These microsetae occur in line with the elytral interneurs, and on the compound eyes are set along the ommatidial margins (Figs 1B , 8B , 9B ). Again, this configuration differs from that of Nearctic taxa such as P. austinicus Casey, P. proximus , and P. scitulus (CUIC), in which only the meso- and metathoracic femora bear such a pelage and all other body surfaces are glabrous excepting macrosetae. It should be noted that some Tachys spp. also have the ventral surface of the meso- and metathoracic femora covered with a sparse pelage; e.g., T. litoralis Casey, T. mordax LeConte, and T. vittiger LeConte. Setitachys macrops Baehr (2016) of northern Australia also bears a setose pelage over the body, but this species differs dramatically from the Hawaiian Paratachys in mandibular length, pronotal shape, elytral striation, and aedeagal configuration, suggesting an independent origin for the pelage in the two lineages. Species of the Lymnastis Motschulsky- Micratopus Casey lineage ( Maddison et al. 2019) are also characterized by such a full-body pelage ( Baehr 2016).

Identification and generic placement.

Boyd and Erwin’s (2016) key to New World Tachyina supports generic assignment of Hawaiian Paratachys through use of the characters that diagnose the genus worldwide. Andrewes’ (1925) key to Oriental Tachys Dejean sensu lato is based on a similar though simplified set of characters that assigns Hawaiian Paratachys species to his " triangularis " group. Finally, Britton (1948) could be used firstly to generically determine Hawaiian Paratachys as Tachys , and then as the only previously described species, Paratachys arcanicola (Blackburn) ( Britton 1948: 238), although Britton’s keys do not utilize diagnostic characters ( Boyd and Erwin 2016) that underlie taxonomic definition of Paratachys .

Coulon (2004) distinguished European species of Eotachys Jeannel from those of Paratachys based on the complete eighth elytral interneur of the Nearctic P. austinicus Casey, type species of Paratachys , vs. an interrupted eighth interneur in the European Tachys bistriatus Duftschmid, type species of Eotachys . However, as the European Tachys bistriatus is nested within a clade of New World Paratachys spp., with the Hawaiian Paratachys terryli (reported as Paratachys sp. "U.S.A.: Hawaii") placed as their respective adelphotaxon in a comprehensive molecular phylogenetic analysis ( Maddison et al. 2019, fig. 12), the synonymy of Eotachys under Paratachys reported first by Erwin (1971) is corroborated, and herein accepted.

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 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 8. Paratachys haleakalae A dorsal habitus view B mentum and associated mouthparts, ventral view C larger compound eye of female, lateral view D smaller compound eye of male; lateral view E stenopterous left metathoracic flight wing of female (elytron removed), dorsal view.

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.