Amaroxenus marrisi 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 marrisi Liebherr & Will sp. nov.

Types.

Holotype male ( LUNZ): New Zealand BR / Ridge above Mt. Cedric, 1695 m / GPS 41°53.380S, 172°43.520E / 13 Dec 2008, J. W. M. Marris / Under rock in outcrop // ♂ // HOLOTYPE ♂ / Amaroxenus / marrisi / Liebherr and Will 2023 (black-bordered red label) . Paratypic allotype female ( LUNZ): same data as holotype // ♀ // ALLOTYPE ♀ / Amaroxenus / marrisi / J. K. Liebherr 2023 (black-bordered red label) . Paratypes: New Zealand, Buller, Nelson Lakes N. P., ridge ENE Mt. Cedric , 1698 m, 41°53.36'S, 172°43.50'E, 13-xii-2008, J. K. Liebherr, under fractured graywacke on moist ground, snowmelt ( CUIC, 2 ♂♂, 2 ♀♀; NZAC, 1 ♂, 1 ♀) .

Diagnosis.

Pronotum slightly transverse, MPW / PL = 1.27, narrower than prothorax of the similar A. kahurangiensis with MPW / PL = 1.39; eyes small, indistinctly convex, ocular ratio = 1.27, versus ocular ratio = 1.31 for A. kahurangiensis ; parascutellar stria and stria 2 punctate, continuous on disc, versus shallower, finely incised with smaller, isolated punctures in A. kahurangiensis ; three dorsal elytral setae set just mesad stria 3, the anterior two at 0.25 × and 0.34 × elytral length, the posterior seta posteriad mid-length, near 0.57 × elytral length versus only two dorsal elytral setae set before elytral mid-length in A. kahurangiensis ; standardized body length = 6.9–7.4 mm, tending larger in the extreme than A. kahurangiensis at 6.9–7.05 mm. [Note that this size range, based on a male and female ( LUNZ) from the same series as the types ( Larochelle and Larivière 2022: 13), were measured using the protocol described above. Even though the landmarks used in this study deviate little from those suggested for measuring body length in the works of Larochelle and Larivière (e. g., 2007, fig. 119), our body length measurements for A. kahurangiensis are significantly greater than the 5.3–6.6 mm value reported in Larochelle and Larivière 2022).

Description.

Head. Frons broad, flat, with only very shallow frontal impressions traceable each side of midline, middle of frons narrowly flattened, with shallow wrinkles obliquely emanating from flat area approaching the shallow frontal impressions; eyes with horizontal diameter intersecting ~ 20 ommatidia. Prothorax broadly convex dorsally, middle of disc flat, lateral margins moderately sinuate anteriad slightly obtuse hind angles, MPW / BPW = 1.11; basal margin trisinuate, medial margin extended slightly posteriad line intersecting hind angles; base with distinct, narrow marginal bead medially, bead less upraised and flatter laterally but continuous to hind angle; median base smooth, convex; laterobasal depressions ovoid, defined mesally by a smooth declivity, surface of depression smooth, only slightly dimpled, depression isolated from lateral margin by broad convexity; median impression very finely inscribed on elevated disc, intersecting ~ 5 broad transverse impressions between elevated disc and median base; lateral marginal bead very narrow, only slightly upraised, lateral marginal depression exceedingly narrow and immediately abutting convex disc; anterior margin with broad, irregularly flattened lateral bead in medial 4 / 5 of breadth, distinctly upraised only immediately mesad front angles; front angles acute, inner margin adhering to the lateral surface of the head, APW / BPW = 0.86; prosternum smooth medially, lateral reaches slightly depressed anteriad prosternal-proepisternal suture; posterior margin of prosternal process extended as adze-like projection, its ventral surface bearing a narrow longitudinal declivity that deepens toward apex of projection; proepisternum / proepimeron juncture lined with ~ 5 rugose longitudinal depressions. Elytra narrowly ovate, MEW / EL = 0.74, narrow basally, HuW / HEW = 0.58, humeri narrowly expanded posteriad rounded humeral angle defined by basal and lateral margins; elongate parascutellar stria free from stria 2 at basal groove; parascutellar stria free apically, terminated at 0.73 × elytral length; elytral stria 2 obsolete near elytral apex, impunctate and discontinuous apicad termination of parascutellar stria, striae 3–7 progressively reduced on apex, discontinuous to obsolete, stria 8 a discontinuous series of distant punctures near humerus, punctures more closely set near mid-length, stria shallow and impunctate in apical half of elytra; stria 9 — i. e. lateral marginal depression — closely set with ~ 10 punctures posteriad humerus, minutely punctate at mid-length and smooth apically; 11–13 lateral elytral setae situated just laterad stria 8. Pterothorax foreshortened, mesepisternum broadly, shallowly punctate with ~ 16 punctures across surface; mesosternum smooth, with narrowly cristate median crest aligned with prosternal projection; mesepimeron a narrow parallel-sided strap bordering posterior margin of mesepisternum, both sclerites broadly reaching disjunct mesothoracic coxal cavity; metepisternum subquadrate, appearing slightly longer than broad due to concave medial margin along juncture with mesosternum, surface undulated with ~ 5 minute punctures near medial margin; lateral reaches of mesosternum irregularly undulated along metacoxal juncture. Abdomen with first visible ventrite smooth, slightly longitudinally wrinkled; lateral reaches of ventrites 2–3 longitudinally wrinkled; ventrites 4–6 smooth except for broad depression halfway between abdominal articulatory setae and lateral margin; apical ventrite of both males and females with one seta each side of midline. Legs with expanded tarsomeres on pro- and mesothoracic legs; males with protarsomere 2 w / l = 1.2, mesotarsomere 2 w / l = 1.0, 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, those on tarsomere 4 tightly packed, silky looking; female protarsomeres 1–4 and mesotarsomeres 2–4 clothed with dense, apical fields of thick, silky, presumably flexible setae.

Male genitalia. Aedeagal median lobe robust, broad dorsoventrally and bilaterally from base to narrow, parallel-sided and apically rounded apex (Fig. 6 D – F ), median lobe basal bulb closed, bearing an apically divergent sagittal crest (Fig. 6 D, E ); 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 three dense rows of long setae (Fig. 6 F ); left paramere conchoid, parallel sided, glabrous, acuminate apicoventrally (Fig. 6 E ); aedeagal internal sac with heavily sclerotized fields including dorsal flagellum and a dense ventral spicular field (Fig. 6 D ).

Female reproductive tract.

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

Etymology.

This species is named to honor John W. M. Marris for his support of New Zealand entomology, including his efforts to document the high elevation alpine insects of New Zealand; among others the very interesting, lichenophilic Protodendrophagus antipodes Thomas ( Coleoptera , Silvanidae ; see Marris et al. 2019).

Distribution.

This species is known only from type locality on the ridge above and ENE of Mt. Cedric, in Buller District. The collecting site is along the valley rim above the headwaters of Open Creek south branch, which flows southwest into the Sabine River.

Habitat.

Adult beetles were found within cracks of exposed and crumbling blocks of graywacke in an area of recently melted snow, with the rocky substrate still moist. The rocks had been separated through frost action, with the cracks infiltrated by plant roots, thereby providing moist laminar spaces for insect habitation. The Amaroxenus beetles were cohabiting the rock crevices along with adults and larvae of Protodendrophagus antipodes .

Figures

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.