Saprinus (Saprinus) chathamensis, Lackner, Tomas & Leschen, Richard A. B., 2017

Lackner, Tomas & Leschen, Richard A. B., 2017, A monograph of the Australopacific Saprininae (Coleoptera, Histeridae), ZooKeys 689, pp. 1-263 : 92-97

Saprinus (Saprinus) chathamensis sp. n. Figs 372, 373-381, 382-388, 761

Type locality.

New Zealand: Chatham Islands: Point Weeding: Waitangi.

Type material examined.

Holotype, ♂, side-mounted on a triangular card, with terminalia extracted and mounted in Canada Balsam on a separate slide under the specimen, with the following labels: "Chatham I. / Exp. Feb. 1967" (printed); followed by: "Pt. Weeding / Waitangi" (printed); followed by: "14.ii.[19]67 / beach" (printed-written); followed by: "G. Kuschel" (printed); followed by: “09-083” (yellow label, pencil-written); followed by: " Saprinus (Saprinus) / chathamensis sp. n. / HOLOTYPE / Lackner & Leschen 2010" (red label, printed) (NZAC). Paratypes, 6 ♀♀, 2 ♂♂ & 4 specs., same data as holotype, except for yellow label, that is present only on holotype (NZAC; 3 paratypes in coll. TLAN). 1 spec., same data as holotype, but "Owenga / 25.ii.[19]67" (NZAC). 4 ♀♀ & 10 specs., with following labels: "NEW ZEALAND CI / Pitt I, Waihere Bay / 21.i.1997 / J.W.M. Marris / under rotting pilot whale" (written); followed by: "ENTOMOLOGY / RESEARCH MUSEUM / (LUNZ) / Lincoln University, / Canterbury, New Zealand" (green label, printed); followed by: " Saprinus (Saprinus) / chathamensis sp. n. / PARATYPE / Lackner&Leschen 2010" (red label, printed) (LUNZ; 3 paratypes in coll. TLAN). 1 spec., with following labels: "NEW ZEALAND CH / Chatham I / Owenga Beach / 6 Dec 2004 / RM Emberson, P. Syrett" (printed); followed by: "Under kelp" (printed); followed by: "ENTOMOLOGY / RESEARCH MUSEUM / (LUNZ) / Lincoln University, / Canterbury, New Zealand" (green label, printed); followed by: " Saprinus (Saprinus) / chathamensis sp. n. / PARATYPE / Lackner&Leschen 2010" (red label, printed) (LUNZ). 1 spec., with following labels: "NEW ZEALAND CI / Pitt I, Waihere Bay / 21.i.1997 / R.M. Emberson / under rotting pilot whale" (printed); followed by: " AMNZ 49382 / AUCKLAND / MUSEUM / NEW ZEALAND"; followed by: " AMNZ 49382 / AUCKLAND / MUSEUM NEW ZEALAND" (green label, printed) followed by: " Saprinus (Saprinus) / chathamensis sp. n. / PARATYPE / Lackner&Leschen 2010" (red label, printed) (AMNZ).

Biology.

Found under rotting pilot whale and under kelp.

Distribution.

New Zealand: Chatham Islands (Chatham and Pitt Islands; Fig. 761).

Diagnosis.

S. chathamensis is a species morphologically, including male genitalia, very similar to other two New Zealand endemics ( S. detritus and S. pseudodetritus sp. n.), with which it most likely shares a recent common ancestor. It is a dark-brown species without metallic luster with a strongly reduced third dorsal elytral stria. It differs from the other two species chiefly by almost completely impunctate pronotum (punctate in the other two species) and different male terminalia. Its eighth sternite is strongly sclerotized and narrowing apically (Fig. 382), whereas the eighth sternite of other two species is not so strongly sclerotized and wider apically. Likewise, the eighth sternite of S. chathamensis is apically adorned only with several short setae (instead of a tuft of setae in the other two species).

The three New Zealand species of Saprinus ( S. chathamensis sp. n., S. detritus and S. pseudodetritus sp. n.) share the following character states: absence of pronotal depressions, shortened third dorsal elytral stria, setose pronotal hypomeron, interrupted frontal stria as well as strongly sclerotized eighth sternite of male terminalia (entirely fused), apically on each side with a tuft of setae, gradually dilated apical half of spiculum gastrale and separated parameres of male genitalia, with a short basal piece of aedeagus.

Diagnostic description.

Since S. chathamensis is rather similar to S. detritus and S. pseudodetritus we will provide only its diagnostic description here mostly outlining the chief differences between the three taxa. The figures, as well as male genitalia drawings are kept, for the sake of easier identification of the Australopacific taxa. The same approach is taken with the species S. pseudodetritus . On the other hand, the species S. detritus , which was described originally as the first of the three New Zealand species, will be provided with full detailed description. Dark-brown, shining species with almost black pronotum (Fig. 372), cuticle without metallic luster, body length: PEL: 2.65-3.75 mm; EL: 1.65-2.50 mm; APW: 1.50-1.60 mm; PPW: 2.00-2.85 mm; EW: 2.20-3.15 mm. Antennae (Figs 373-374) similar to those of S. detritus (Figs 423-424) or S. pseudodetritus (Figs 512-513); sensory structures of antennal club not examined. Mouthparts generally very similar between the three species, mentum (Fig. 375) also similar to those of S. detritus (Fig. 425) and S. pseudodetritus (Fig. 514), but disc of mentum finely imbricate, and almost asetose (covered with setae in the other two species). Clypeus and frons (Fig. 373) similar to other two species (compare with Figs 423 and 512) frontal stria deeply impressed, interrupted medially (occasionally narrowly). Pronotal sides (Fig. 372) moderately narrowing apically, pronotum except for a double row of sparse punctures along pronotal base glabrous (other two species have a band of punctures along lateral margins; compare Figs 422 and 511). Elytral structure as well as configuration of elytral striae generally similar between the three species (compare Figs 372, 422 and 511), with characteristically shortened third elytral stria. Elytral punctation confined to apical elytral third, elytral flanks impunctate, punctures rather deep, forming strioles, interspaces without microsculpture, punctures separated by about their own diameter (Fig. 372). Propygidium and pygidium (Fig. 376) with fine small round punctures separated by about their diameter, interspaces imbricate; similar to that of S. pseudodetritus (Fig. 515). Prosterna generally similar between the three species (compare Fig. 377 with Figs 426 and 516), but carinal prosternal striae rather narrowing apically, whereas they are almost parallel-sided in S. pseudodetritus (Fig. 516) and somewhat divergent and widening apically in S. detritus (Fig. 426); course of lateral prosternal striae similar between species. Mesoventrites of the three species (Figs 378, 427 and 517) trapezoidal, discal marginal mesoventral stria well impressed, carinate, complete, anteriorly straight in S. chathamensis (Fig. 378), while slightly inwardly arcuate in S. detritus (Fig. 427) and S. pseudodetritus (Fig. 517); disc in S. chathamensis with sparse fine punctation, while punctation in other two species somewhat more prominent (compare with Figs 427 and 517); meso-metaventral stria in all three species undulate. Metaventrites and lateral disc of metaventrites as well as metepisterna very similar between the three species (compare Figs 379, 428 and 518). Legs generally similar between species, for the detailed description of legs see description of S. detritus and compare Figs 380-381 with 429 (protibia) and 430-431 with 519-520 (meso-and metatibia).

Male genitalia. Eighth sternite (Figs 382-383) apically with several pseudo-pores, entirely fused, strongly sclerotized, fused sternite basally with median projection among otherwise widely separated halves; apex of eighth sternite laterally with two tufts of several moderately long setae; eighth tergite and eighth sternite fused laterally (Fig. 384). Ninth tergite (Figs 385-386) typical for the subfamily; anterior margin of tenth tergite straight; spiculum gastrale (Fig. 385) gradually dilated on apical half; apical end strongly sclerotized; basal end abruptly dilated, almost heart-shaped. Aedeagus (Figs 387-388) slightly gradually dilated from base towards apex, but before apex slightly constricted; parameres fused along their basal half (roughly); basal piece of aedeagus short, ratio of its length: length of parameres 1: 6; aedeagus almost straight, only apically slightly curved from lateral view (Fig. 388). In general, eighth sternite and tergite of S. chathamensis are more strongly sclerotized and narrowing apically, while they are not so strongly sclerotized and more wide apically in the other two species (compare Figs 382-383 with Figs 432-433 and 521-522). Aedeagus of S. chathamensis is more similar to that of S. pseudodetritus than to that of S. detritus (compare Figs 387, 437 and 526).