Amaroxenus embersoni Liebherr & Will, 2024

Liebherr, James K., Roig-Juñent, Sergio & Will, Kipling W., 2024, Phylogenetic analysis of the circum-Antarctic Subfamily Migadopinae (Coleoptera, Carabidae) and assessment of the trans-Tasman Amarotypus clade, Deutsche Entomologische Zeitschrift 71 (2), pp. 319-338 : 319-338

Amaroxenus embersoni Liebherr & Will sp. nov.

Types.

Holotype male ( LUNZ) mislabeled: Arthurs Pass Nat. / Pk, NC 1650 m / Mt. Philistine / 1-i-1988 P. Syrett / R. M. Emberson // under rock / in fine damp / gravel // HOLOTYPE ♂ / Amaroxenus / embersoni / Liebherr and Will 2023 (black-bordered red label). Based on consultation with Emberson field notes (P. Syrett pers. comm.) the holotype was actually collected at: Arthur’s Pass N. P., Mt. Aicken , 1750 m, 1-i-1988 (Fig. 7 ) . Paratypes: same incorrect data label as holotype ( LUNZ, 1 ♂) ; New Zealand: Arthur’s Pass N. P., Mt. Aicken , 1750 m, 1-i-1988, R. M. Emberson and P. Syrett, under rock sparse fell field vegetation ( LUNZ, 1 ♀) [as noted above, these data are appropriate for all three specimens of A. embersoni ].

Diagnosis.

A broad-bodied species, with transverse pronotum, MPW / PL = 1.42, and broadly ovate elytra, MEW / EL = 0.76 (Fig. 2 B ); elytra moderately convex but with disc flat; elytral striae punctate in basal ¾ of length, intervals moderately convex on disc; standardized body length 7.8–8.1 mm.

Description.

Head. Frons broad, frontal grooves broad and shallow depressions isolated from clypeus, lined with shallow oblique wrinkles on mesal surface; eyes slightly convex, horizontal diameter intersecting ~ 20 ommatidia, ocular ratio = 1.28. Prothorax broadly convex dorsally, middle of disc flat, lateral margins distinctly sinuate anteriad slightly acute hind angles, MPW / BPW = 1.05; basal margin trisinuate, medial margin extended slightly posteriad line intersecting hind angles; base indistinctly, narrowly margined, marginal bead narrowest posteriad laterobasal depression; median base smooth, with shallow ovoid depression at midline; laterobasal depressions broad, defined mesally by irregular declivity, surface dimpled laterad declivity and depression curved upward to broadly meet the narrow lateral margin; median impression very fine, intersecting ~ 12 fine, transverse impressions that represent little more than irregularities in microsculpture; lateral marginal bead narrowly upraised, lateral marginal depression very narrow and immediately abutting convex disc; anterior margin with distinct, broad lateral bead laterally, but margin nearly smooth medially, margin traceable only in certain orientations of light source; front angles acute, inner margin adhering to lateral surface of head, APW / BPW = 0.74; prosternum smooth medially, lateral reaches slightly undulated; posterior margin of prosternal process extended as adze-like projection, its ventral surface bearing a deep longitudinal declivity; proepisternum / proepimeron juncture lined with ~ 7 rugose longitudinal depressions. Elytra narrow basally, HuW / MEW = 0.59, humeri evenly expanded posteriad narrowly rounded humeral angle defined by basal and lateral margins; elongate parascutellar stria joined basally to stria 2, the fused trunk curved laterally parallel to sutural stria; parascutellar stria free apically, terminated at 0.70 × elytral length; elytral stria 2 extended nearly to apex, finely punctate even apically, striae 3–6 progressively shorter on apex, stria 7 fused both basally and apically to stria 8, both striae distinctly punctate anteriad posterior juncture, stria 8 irregularly punctate posteriad juncture; stria 9 — i. e. lateral marginal depression — punctate nearly to juncture of striae 7 and 8; elytral interval 3 bearing two very fine setae in obscure depressions set at and posteriad elytral mid-length, the impressions situated just mesad stria and associated with slight deviations in the strial orientation; 11–13 lateral elytral setae situated just laterad stria 8. Pterothorax foreshortened, mesepisternum broadly punctate, with ~ 20 punctures in posterior 2 / 3 of length; mesosternum smooth, with fine median crest aligned with adze-like prosternal projection; mesepimeron a narrow longitudinal strap bordering posterior margin of mesepisternum, both sclerites reaching disjunct mesothoracic coxal cavity; metepisternum irregularly quadrate, anterior and posterior margins parallel, medial margin concave along juncture with mesosternum; lateral reaches of metasternum punctate, ~ 8 punctures over surface. Abdomen finely punctate basally on first visible ventrite; lateral reaches of ventrites 2–3 longitudinally wrinkled, ventrites 4–6 very finely punctulate over surface; apical ventrite of one male and the female specimen with one seta each side of midline, second male with two setae on right, and one on left side of the ventrite. Legs with expanded tarsomeres on pro- and mesothoracic legs; males with protarsomere 2 w / l = 1.33, mesotarsomere 2 w / l = 1.04, and females with protarsomere 2 w / l = 1.37, mesotarsomere 2 w / l = 0.81; male pro- and mesotarsomeres 1–4 both with ventral surfaces clothed with laterally expanded setae, those on protarsomeres 1–3 broadly expanded laterally, squamose; female protarsomeres 1–4 and mesotarsomeres 2–4 clothed with dense, apical fields of thick, silky, presumably flexible setae.

Male genitalia (Fig. 6 A – C ). Aedeagal median lobe robust, broad dorsoventrally and bilaterally from base to apically rounded apex (Fig. 6 A, B ), median lobe basal bulb closed, bearing an apically divergent sagittal crest; median lobe sclerotized basally, ostium opening apically on left side; right paramere broadly conchoid, parallel sided with narrowly rounded ventral apex, ventral margin lined with 3 dense rows of long setae; left paramere conchoid, parallel sided, glabrous, acuminate apicoventrally (Fig. 6 B ); aedeagal internal sac with heavily sclerotized fields including a dorsal flagellum and a dense ventral spicular field (Fig. 6 A ); mediotergite VIII broadly rounded distally, sclerotized apex broadened relative to tubular lateral margin (Fig. 6 C ).

Female reproductive tract.

Gonocoxite narrow, elongate, unipartite, articulated basally with heavily sclerotized median boss along anterior margin of laterotergite IX (Fig. 3 B ); two nematiform setae in apical sensorial pit; ventroapical surface of gonocoxite lined with campaniform sensoria, with several small trichoid sensilla in median half of coxite; bursa copulatrix circular (when compressed on microslide), with common oviduct-bursal juncture on ventral surface, and cristate “ helminthoid sclerite ” near juncture (Fig. 4 B ); ventroapical surface of bursa broadly, moderately sclerotized, resulting in a discrete plate just distad the bursal-oviduct juncture.

Etymology.

We take great pleasure in naming this species for Professor Rowan M. Emberson (Fig. 7 ), late of Lincoln University. He collected the three type specimens during a hike, accompanied by Pauline Syrett, to the summit of Mt. Aicken in the Southern Alps of New Zealand, December, 1987. The species epithet recognizes Professor Emberson’s dedication to the study of New Zealand’s insects, including discovery of this high montane New Zealand insect species comprising animals that live in extreme situations far beyond the limits of most entomological exploration.

Distribution.

Mt. Aicken is located at 42°55.85'S, 171 ° 35.70 ′ Е, and has a summit elevation of 1859 m (https://climbnz.org.nz/nz/si/arthurs-pass/mt-aicken).

Habitat.

This is a species of high montane grassland and exposed glacial till. At elevations of 1650–1750 m in the Southern Alps, these habitats are strictly alpine in character. The three specimens were collected under rocks at the edge of receding snowfields (Fig. 7 )

Figures

Figure 2. Representative taxa of the Amarotypus clade, dorsal view. A. Amarotypus edwardsii; B. Amaroxenus embersoni; C. Amaroxenus marrisi; D. Amarophilus otagoensis; E. Migadopiella convexipennis; F. Migadopiella octoguttata.

Figure 3. Female left gonocoxite, ventral view. A. Amarotypus edwardsii; B. Amaroxenus embersoni; C. Amaroxenus marrisi; D. Migadopiella octoguttata; E. Amarophilus otagoensis.

Figure 4. Female reproductive tract, ventral view, scale bar = 0.5 mm to right of each figure. A. Stichonotus piceus; B. Amarotypus edwardsii; C. Migadopiella octoguttata; D. Amaroxenus embersoni; E. Amaroxenus marrisi; F. Amarophilus otagoensis. Abbreviations for anatomical structures include: bc, bursa copulatrix; bd, bursal diverticulum; co, common oviduct; dbs, distal bursal sclerite; gc, gonocoxa; ls, ligular sclerite; lt, laterotergite.

Figure 6. Male aedeagal complex. A – C. Amaroxenus embersoni. A. Median lobe and parameres, dextral view; B. Median lobe and parameres, sinistral view; C. Metatergite, ventral view. D – F. Amaroxenus marrisi: D. Median lobe and parameres, dextral view; E. Median lobe and parameres, sinistral view; F. Median lobe and parameres, ventral view.

Figure 7. Type locality of Amaroxenus embersoni showing Professor Rowan Emberson collecting the type series (photo courtesy Pol Syrett).