Nesamblyops distinctus, Sokolov, 2023

Sokolov, Igor M., 2023, Eight new species of the genus Nesamblyops Jeannel (Anillini: Carabidae: Coleoptera) from New Zealand with notes about dispersal of the genus to the North Island, Zootaxa 5230 (2), pp. 179-201 : 185-186

Nesamblyops distinctus , sp. nov.

Figs. 2D , 4D , 5J–L , 7C , 9

Type material. HOLOTYPE, male, in NZAC, dissected, labeled: \ Head of Fabians Valley 920m Marlborough 23 Oct 63 \ J.I. Townsend \ Litter 63/28 \ DSIR \ No \ NZ PB \. PARATYPES (3 specimens, in NZAC, dissected 1 male), 1 male and 2 females labeled same as holotype .

Additional material: \ Mt. Riley 2400’ Blenheim Dist. 24.vii.66 A.K. Walker \ litter from dry ridge under rata, beech and cedar trees 66/217 \ DSIR \ No \ (1 female).

Etymology. The specific epithet is a Latin adjective, distinctus , in the masculine form, meaning “distinguished”, and refers to the distinctive shape of the sclerites in the internal sac of male genitalia, allowing to distinguish this species from his closest relatives.

Type locality. New Zealand, South Island, Marlborough, Richmond Range, Fabians Valley .

Recognition. Adults of this species ( Fig. 2D ) can be distinguished from the adults of majority species of Nesamblyops by the distinctive shape of pronotum ( Fig. 4D ), however are practically indistinguishable from the adults of some Nesamblyops species (cf. with Figs. 3C ) and are distinguished from all of them by the structure of the male genitalia.

Description. Large for genus (SBL range 1.93–2.26 mm, mean 2.06± 0.130 mm, n=5).

Habitus. Body form ( Fig.2D )markedly convex,elongate ovoid, general proportions wide (WE/SBL 0.42±0.011), head narrow relative to pronotum (WH/WPm 0.66±0.008, proportions of pronotum in comparison to elytra average for genus (WPm/WE 0.76±0.011).

Color. Body color brunneopiceous, appendages testaceous.

Prothorax. Pronotum ( Fig. 4D ) moderately long in comparison to elytra (LP/LE 0.43±0.022) and moderately transverse (WPm/LP 1.28±0.055), with lateral margins almost rectilinear and slightly constricted posteriorly (WPm/ WPp 1.23±0.016). Anterior angles indistinct, posterior angles obtuse (105–115°), dented, and slightly protruding backwards. Width between posterior angles greater than between anterior angles (WPa/WPp 0.80±0.030). Basal margin slightly concave.

Elytra. Ovoid, narrowly depressed along suture, comparatively long (LE/SBL 0.58±0.008) and wide (WE/LE 0.72±0.026). Humeri completely rounded. Lateral margins slightly divergent at basal half, shortly subparallel at middle and evenly rounded to apex in apical half.

Male genitalia. Median lobe of aedeagus ( Fig. 5L ) moderately arcuate and moderately twisted. Shaft subparallel basally, tapering in apical half. Apex moderately curved dorsally with narrowly narrowly rounded tip. Apical orifice long, occupies almost half of the shaft length. Ventral margin of median lobe straight. Walls of shaft without poriferous canals. Dorsal copulatory sclerites in form of characteristic “bird’s head” plate with apically attenuated dorsal part, and surrounded by distinct scaled membraneous field. Spines of internal sac absent. Left paramere ( Fig. 5J ) comparatively wide, with shortly attenuate apex, bearing three long setae. Right paramere ( Fig. 5K ) of moderate length, bearing three long setae, which are slightly shorter the length of paramere. Ring sclerite as in Fig. 7C .

Female internal genitalia. Not examined.

Geographical distribution. This species is known from two localities on the Richmond Range in the Marlborough area ( Crosby et al. 1998) ( Fig. 9 , red circles).

Habitat. Specimens were collected from litter “under rata, beech and cedar trees”.

Relationships. Based on the structure of the male genitalia N. distinctus forms a natural group with other species having a similar dorsal copulatory sclerite in the internal sac of the median lobe, such as N. brouni , N. tararua , and N. townsendi . Based on the details of the sclerite configuration and the state of the scaled membraneous field, it is postulated that N. distinctus is a sister taxon to N. brouni .

Figures

FIGURE 2. Digital images of habitus of New Zealand Nesamblyops species, dorsal aspect. A—N. brouni (Lewis Pass, North Canterbury, SO), B—N. carltoni (Dun Mountain, Nelson, SO), C—N. confusus (Mount Stokes, Marlborough Sounds, SO), D—N. distinctus (Fabians Valley, Marlborough, SO), E—N. lescheni (D’Urville Island, Cook Strait, Marlborough Sounds, SO), F—N. oreobius (Mount Pirongia, Waikato, NO). Scale bar 1.0mm.

FIGURE 3. Digital images of habitus of New Zealand Nesamblyops species, dorsal aspect. A—N. parvulus (Mount Stokes, Marlborough Sounds, SO), B—N. tararua (Judd Ridge, Tararua Range, Wellington, NO), C—N. townsendi (Tennyson Inlet, Marlborough Sounds, SO). Scale bar 1.0mm.

FIGURE 4. Digital images of pronota of New Zealand Nesamblyops species, dorsal aspect. A—N. brouni (Lewis Pass, North Canterbury, SO), B—N. carltoni (Dun Mountain, Nelson, SO), C—N. confusus (Mount Stokes, Marlborough Sounds, SO), D—N. distinctus (Fabians Valley, Marlborough, SO), E—N. lescheni (D’Urville Island, Cook Strait, Marlborough Sounds, SO), F—N. oreobius (Mount Pirongia, Waikato, NO), G—N. parvulus (Mount Stokes, Marlborough Sounds, SO), H—N. tararua (Judd Ridge, Tararua Range, Wellington, NO), I—N. townsendi (Tennyson Inlet, Marlborough Sounds, SO). Scale bar 0.2mm.

FIGURE 5. Line drawings of male genitalia of New Zealand Nesamblyops species. N. brouni (Lewis Pass, North Canterbury, SO): A—left paramere, left lateral aspect, B—right paramere, right lateral aspect, C—median lobe, right lateral aspect. N. carltoni (Dun Mountain, Nelson, SO): D—left paramere, left lateral aspect, E—right paramere, right lateral aspect, F—median lobe, right lateral aspect. N. confusus (Mount Stokes, Marlborough Sounds, SO): G—left paramere, left lateral aspect, H—right paramere, right lateral aspect, I—median lobe, right lateral aspect. N. distinctus (Fabians Valley, Marlborough, SO): J—left paramere, left lateral aspect, K—right paramere, right lateral aspect, L—median lobe, right lateral aspect. N. lescheni (D’Urville Island, Cook Strait, Marlborough Sounds, SO): M—left paramere, left lateral aspect, N—right paramere, right lateral aspect, O—median lobe, right lateral aspect. N. oreobius (Mount Pirongia, Waikato, NO): P—left paramere, left lateral aspect, Q—right paramere, right lateral aspect, R—median lobe, right lateral aspect. Scale bar 0.1mm.

FIGURE 7. Line drawings of ring sclerite of New Zealand Nesamblyops species, male genitalia, dorsal aspect. A—N. brouni (Lewis Pass, North Canterbury, SO), B—N. carltoni (Dun Mountain, Nelson, SO), C—N. distinctus (Fabians Valley, Marlborough, SO), D—N. oreobius (Mount Pirongia, Waikato, NO), E—N. lescheni (D’Urville Island, Cook Strait, Marlborough Sounds, SO), F—N. parvulus (Mount Stokes, Marlborough Sounds, SO), G—N. tararua (Judd Ridge, Tararua Range, Wellington, NO), H—N. townsendi (Tennyson Inlet, Marlborough Sounds, SO). Scale = 0.4mm.

FIGURE 9. Distributional records for the Nesamblyops species and images of male median lobe, obtained from specimens, collected in the line-connected with images localities. Black circles—N. tararua; yellow circles—N. townsendi; red circles—N. distinctus; green circles—N. brouni. Scale bar= 0.5mm.