Lepanus podocarp Gunter & Weir, 2019

Gunter, Nicole L. & Weir, Thomas A., 2019, Revision of Australian species of the dung beetle genus Lepanus (Coleoptera: Scarabaeidae: Scarabaeinae): key to species groups and description of 14 new species from the L. pygmaeus species group, Zootaxa 4564 (1), pp. 41-80 : 73-74

Lepanus podocarp Gunter & Weir , new species

( Figs. 6E , 9B , 12A , 14 )

Type series. Holotype: ♂ “AUST: NT; Arnhemland 33km E Jabiru, Podocarp Canyon, Rainforest , 15-23. XII. 93, 5 FITs, S&J Peck 93-130” [12°39'59''S, 133°9'30''E] / Canadian Museum of NATURE CMNEN-00030225 ” / “ANIC Database No. 25-065550” / “ Lepanus sp.1” / “ Lepanus NT7 det. T.A.Weir 2018 ” / “ANIC Image” in ANIC. Paratypes: Northern Territory: Arnhemland 33 km E Jabiru, podocarp canyon, [12°39'59''S, 133°9'30''E], 15–23.xii.1993, S.B. & J. Peck ( CMNEN-00030226 , CMNEN-00030230 in ANIC 2 × ♀, CMNEN- 00030227–00030229 in CMNC 1 × ♂, 2 × ♀).

Description. Either uniformly dark brown or with red patches on elytral humeri. Antennal clubs black.

Total length: 2.3–2.6 mm. Holotype measurements: Total length 2.3 mm, elytral width 1.6 mm.

Male: Head: U-shaped between clypeal teeth, which are short and upturned. Margin slightly angulate at clypeogenal suture. Genal angle weakly defined. Basal carina present and narrowly interrupted. Punctation on the clypeus is finer than on rest of head. Dorsal part of eyes moderate, separated by interocular space approximately 15 times eye width (37: 2.5); eye canthus not dividing the eye. Head 1.2 × wider than long (45:37).

Prothorax: Hypomeral surface very finely reticulate without punctation. Hypomeral striae at least half length of hypomeron. Pronotum 1.65 × wider than long (74:45).

Elytra: Surface smooth and striae slightly more impressed towards the apex. Striae 1–5 double with very fine punctate edges, striae 6–7 singular; elytral flange and groove relatively wide; Elytra 1.2 × wider than long (90:74).

Legs: Front edge of protibiae deeply angulate; apical digit somewhat elongate and sharp; 2 teeth on outer edge. Inner edge of metatibiae almost straight. Metatarsi with 2nd tarsomere subequal to the 5th. Tarsal claws small and toothed.

Abdomen: Pygidium with wide pear shaped depression containing a small, slightly elongate tubercle in upper third. Depression occupies at least half size of disc and just extending under the slightly angulate upper edge of pygidium. Abdominal surface very finely reticulate right across. Segment 6 finely punctate.

Pterothorax: Medial lobe of metaventrite finely punctate and broadly margined between mesocoxae. Lateral lobe of metaventrite smooth and punctate with setae. Meso-metaventral suture very slightly arched. Mesoventrite with slight notch anteriorly. Mesoventrite smooth, with discernible punctures at least at sides. Mesepimeron smooth. Metanepisternum reticulate.

Female: As per the L. pygmaeus species group but basal margin of abdominal ventrite 6 slightly convex medially.

Etymology. Named for the only known locality, Podocarp Canyon, West Arnhemland.

Distribution. Known only from Podocarp Canyon, West Arnhemland, in the ARP IBRA region ( Fig. 14 ).

Comments. This species was originally reported as Lepanus sp. 1 in Peck (2002) that documented the beetle fauna of this canyon. Peck (2002) lists erroneous coordinates 12°87'73"S, 133°26'73"E in this study, if the coordinates instead represent 12.8773°S, 133.2673°E they would place the site ~ 52.75km SE of Jabiru, close to but not in forested area as visualised though satellite images. The coordinates 12.6663°S, 133.15833°E more broadly match the description of the locality ~ 33 km from Jabiru on the labels. Digital distributional records for Podocarpus in the Australian Virtual Herbarium (Australasian Virtual Herbarium 2018) indicate 25 records in West Arnhem to the east of Jabiru, however no records are congruent with the 1993 field survey.

Peck (2002) discussed and rejected the likelihood of this rainforested canyon being an invertebrate refugium. This species is distinct from all others known from the region and has only been collected on one occasion by flight intercept trap. Lepanus podocarp was unknown at the time when the informal nomenclature for undescribed species of Lepanus was reported ( Yeates et al. 2011) but was designated the informal name “ Lepanus NT7” within this revision.

Figures

FIGURE 6. Habitus of species within the Lepanus pygmaeus species group. A, Lepanus lingziae; B, Lepanus mckenziei; C, Lepanus menendezae; D, Lepanus pecki; E: Lepanus podocarp; F, Lepanus pungalina. All specimens in comparative scale. Scale bar 1 mm.

FIGURE 9. Pygidial configuration of species within the Lepanus pygmaeus species group. A, Lepanus pecki; B, Lepanus podocarp; C: Lepanus pungalina; D, Lepanus pygmaeus; E, Lepanus sauroni; F, Lepanus tozerensis. All specimens in comparative scale. Scale bar 0.2 mm.

FIGURE 12. Left, dorsal, and right view of aedeagi of species within the Lepanus pygmaeus species group. A, Lepanus podocarp; B, Lepanus pungalina; C, Lepanus pygmaeus; D, Lepanus sauroni; E: Lepanus tozerensis. Not in comparative scale, given size difference aedegi are roughly grouped in three size classes as per lower left schematic and scaled accordingly. Size class indicated by shaded silhouette and 0.2 mm scale bar.

FIGURE 14. Map of known records for 10 species within the Lepanus pygmaeus species group overlaid with predicted distribution boundary of L. pygmaeus (dashed line) taken from Fig. 13 map.