Nesamblyops subrufus, Sokolov, 2023

Sokolov, Igor M., 2023, Fourteen new species of the genus Nesamblyops Jeannel (Coleoptera: Carabidae: Anillini) from the South Island of New Zealand with redescription of the genus and description of a new subtribe, Zootaxa 5375 (2), pp. 151-192 : 182-184

Nesamblyops subrufus , sp. nov.

Figures. 11A , 13D , 16A–C , 20

Type material. HOLOTYPE, male, in NZAC, labeled, dissected: \ Dublin Terrace 25.11.61 G.Kuschel \ Leafmould \ DSIR \ Ns \ NZ PB \. PARATYPES (2 specimens), 2 females labeled same as holotype.

Etymology. The specific epithet is a Latin adjective subrufus (meaning “somewhat red”) in the masculine form and refers to the color of the new species.

Type locality. New Zealand, South Island, West Coast, Upper Buller Gorge, Dublin Terrace .

Recognition. Adults of this species ( Fig. 11A ) are practically indistinguishable from the adults of many Nesamblyops species based on external characters (e.g., Figs. 10D–E ) and are distinguished from them by the structure of the male genitalia.

Description. Large for genus (SBL range 1.80–1.91 mm, mean 1.87± 0.061 mm, n=3).

Habitus. Body form ( Fig. 11A ) markedly convex, elongate ovoid, general proportions slightly wide (WE/SBL 0.37±0.006), head moderately wide relative to pronotum (WH/WPm 0.75±0.025), proportions of pronotum in comparison to elytra average for genus (WPm/WE 0.74±0.005).

Color. Body color rufotestaceous, appendages testaceous.

Prothorax. Pronotum ( Fig. 13D ) moderately long in comparison to elytra (LP/LE 0.39±0.004) and moderately transverse (WPm/LP 1.18±0.018), with lateral margins rectilinear constricted posteriorly (WPm/WPp 1.21±0.029). Anterior angles indistinct, posterior angles obtuse (119–124°), widely rounded. Width between posterior angles greater than between anterior angles (WPa/WPp 0.91±0.046). Basal margin slightly convex.

Elytra. Ovoid, moderately depressed along suture, comparatively long (LE/SBL 0.59±0.002) and moderately narrow (WE/LE 0.63±0.008). Humeri completely rounded. Lateral margins slightly divergent at basal third, subparallel at middle and evenly rounded to apex in apical third.

Male genitalia. Median lobe of aedeagus ( Fig. 16C ) moderately arcuate and barely twisted. Shaft with sides diverging from basal orifice towards middle, then slightly tapering apically. Apex straight, short, enlarged, widely rounded. Apical orifice of moderate length occupies one third of the shaft length. Ventral margin of median lobe almost straight. Walls of shaft lacking poriferous canals. Dorsal copulatory sclerites moderately deviate from typical state. Dorsal field with V-contour small, but distinct, and medial rC-sclerite wide and weakly sclerotized ( Fig. 16C ). Additionally, internal sac has a large scaly membraneous field near apical orifice. Left paramere ( Fig. 16A ) comparatively narrow, with strongly attenuate apex, bearing two long setae. Right paramere ( Fig. 16B ) narrow, long, bearing two long setae, which are shorter than the length of paramere. Ring sclerite not investigated.

Female internal genitalia. Not examined.

Geographical distribution. This species is known from only one locality situated near Manuka Flat in the Upper Buller Gorge, upstream from Inangahua at the northern West Coast region ( Fig. 20 , red circle).

Habitat. All three known to date specimens were collected from leafmould.

Relationships. The external morphology (body proportions, size) suggests relatedness of N. subrufus with N. rotundicollis and N. solitarius . The structure of the parameres (two setae, attenuate apex of left paramere) and the male genitalia (presence of scaly field in apical part of median lobe) support this statement. However, the state of copulatory sclerites of N. subrufus are quite different from those of N. rotundicollis and N. solitarius , but much closer to the copulatory sclerites of the other members of Nesamblyops , thus making a link between two agglomerations of taxa.

Figures

FIGURE 10. Digital images of habitus of New Zealand Nesamblyops species, dorsal aspect. A—N. montanus (Lake Sylvester, Kahurangi National Park, Nelson, SO), B—N. moorei (Kangaroo Creek, Mawhera Forest, Buller, SO), C—N. ovipennis (Mount Arthur, Nelson, SO), D—N. rotundicollis (Onekaka, Nelson, SO), E—N. solitarius (Italian Creek, Capleston, Buller, SO), F—N. subcaecus (Sharp) (Greymouth, Buller, SO). Scale bar = 1.0 mm.

FIGURE 11. Digital images of habitus of New Zealand Nesamblyops species, dorsal aspect. A—N. subrufus (Dublin Terrace, Upper Buller Gorge, Nelson, SO), B—N. viator (Secretary Island, Grono Bay, Fiordland, SO), C—N. victoriae (Capleston, Victoria Range, Buller, SO). Scale bar = 1.0 mm.

FIGURE 13. Digital images of pronota of New Zealand Nesamblyops species, dorsal aspect. A—N. rotundicollis (Onekaka, Nelson, SO), B—N. solitarius (Italian Creek, Capleston, Buller, SO), C—N. subcaecus (Greymouth, Buller, SO), D—N. subrufus (Dublin Terrace, Upper Buller Gorge, Nelson, SO), E—N. viator (Secretary Island, Grono Bay, Fiordland, SO), F—N. victoriae (Capleston, Victoria Range, Buller, SO). Scale bar = 0.2 mm.

FIGURE 16. Line drawings of male genitalia of New Zealand Nesamblyops species. N. subrufus (Dublin Terrace, Upper Buller Gorge, Nelson, SO): A—left paramere, left lateral aspect, B—right paramere, right lateral aspect, C—median lobe, right lateral aspect. N. viator (Secretary Island, Grono Bay, Fjordland, SO): D—left paramere, left lateral aspect, E—right paramere, right lateral aspect, F—median lobe, right lateral aspect. N. victoriae (Capleston, Victoria Range, Buller, SO): G—left paramere, left lateral aspect, H—right paramere, right lateral aspect, I—median lobe, right lateral aspect. Scale bar = 0.1 mm.

FIGURE 20. Distributional records for the Nesamblyops species and images of male median lobe, obtained from specimens, collected in the line-connected with images localities. Green circles—N. solitarius; black circles—N. montanus; pink circles— N. rotundicollis; red circles—N. subrufus. Scale bar = 0.5 mm.