Pselaphaulax caeruleus, Owens & Leschen & Carlton, 2019

Owens, Brittany E., Leschen, Richard A. B. & Carlton, Christopher, 2019, The Pselaphini (Coleoptera: Staphylinidae: Pselaphinae) of the Subantarctic and Chatham Islands of New Zealand; Description of Five Species and One Genus, Insect Systematics and Diversity 3 (2019), No. 2, pp. 1-14 : 4

Pselaphaulax caeruleus , sp. nov. ( Fig. 2 a–d)

(Zoobank LSID: urn:lsid:zoobank.org:act:1F3D2EB4-1485-4E31-A857-33BB2BD4830B )

HOLOTYPE: (male) CHATHAM IS NZ Chatham I Awatotara 180m // 12 February 1967 G.W.Ramsay litter 67/139 ( NZAC).

PARATYPES: (4 males, 3 females) same locality as holotype ( NZAC). (1 male, 1 female) CHATHAM.I. N.Z. Awatotara Table land bus. 183m 21.feb.1967 // G.W.Ramsay Litter 67/139 ( NZAC). All types of this species are deposited in the NZAC.

Etymology

The specific epithet is the Latin word for ‘blue’, commemorating Old Blue, the only remaining adult female Chatham Island robin in 1980. All Chatham Island robins today are descended from this single individual. She lived to be 14 yr old, the longest-lived individual known for her species ( Butler and Merton 1992).

Diagnosis

Head with sulcus on rostrum; frontal margin of rounded with small patch of sparse setae; gular mound rounded, glabrous, and subhemispherical; maxillary palpomeres elongate, maxillary palpomere 4 subequal to length of head, narrow through 1/2 length, widest just beyond 1/2 length, apical sensory patches present and delineated by faint carina. Pronotum with antebasal sulcus, lateral antebasal fovea, and median basal fovea reduced to pit. Mesoventrite with small patch of setae in concavity towards hind margin of procoxae. Metaventrite with broad depression extending from hind margin of mesocoxae to apex of ventrite between metacoxae. Second ventrite with large shallow oval median depression occupying length of ventrite. Externally, the presence of two patches of fine setae on the thickened apex of the second ventrite distinguishes this species of Pselaphaulax from the other two known from the Chathams. The form of the aedeagus, with the median lobe curved to the right is also unique.

Description. Male

Body length: 2.6–2.8 mm. Integument: head, pronotum, elytra, abdomen, and appendages light brown, palpi lighter in color. Head: wide, width between eyes greater than 1/2 length of head from base of vertex to apex of rostrum. Eyes rounded, composed of 15–22 facets. Frontal margin of rostrum in dorsal view rounded with sparse suberect setae. Gular mound modified, hemispherical, as long as wide, glabrous; area of head posterior to gular mound flattened, slightly concave, bearing flattened modified scales. Maxillary palpomere 4 as long as head, widened at base and distal 1/2, apical area smooth, shining, V-shaped sensory patches present, margined by carinae. Thorax: pronotum basal sulcus broad, well-defined, delimited by lateral antebasal foveae; median fovea reduced to pit. Mesoventrite with median shield bearing patch of spongeose setae in small concavity towards hind margin of procoxae. Metaventrite afoveate, medially depressed; metacoxae separated by extension of first ventrite. Legs unmodified. Elytra with three basal foveae, single sutural fovea; single discal stria, sutural striae present; apical fringe of setae present. Abdomen: Tergites of usual form for tribe. First ventrite covered in dense, shining setae; second ventrite with basal sulcus extending width of entire ventrite, sulcus densely setose, large shallow oval median depression occupying length of ventrite, apex of ventrite with small thickened area at middle bearing two patches of fine setae on distal margin. Genitalia: aedeagus asymmetrical. Median lobe distally curved to the right, protruding from fleshy dorsal extension. Ventral process downward curved, distally, about as long as median lobe. Parameres present, as long as median lobe.

Figures

Fig. 2. Pselaphaulax caeruleus. (a) distribution map, Chatham Island; (b) male, dorsal habitus; (c) aedeagus, lateral; (d) aedeagus, dorsal.