Navigator Moeseneder & Hutchinson

Moeseneder, Christian H. & Hutchinson, Paul M., 2016, Navigator, a new endemic genus of Cetoniinae (Coleoptera: Scarabaeidae) from Australia, with descriptions of two new species and behavioural studies, Zootaxa 4173 (6), pp. 530-556 : 533-536

Navigator Moeseneder & Hutchinson , new genus

( Figs. 1–11 , 13 , 14 C–D)

Type species. Pseudoclithria fossor Lea, 1914 , hereby designated.

Included species. Pseudoclithria fossor Lea, 1914 , Pseudoclithria ruficornis ( Westwood, 1874) , Navigator pixii Moeseneder & Hutchinson new species, and Navigator interior Moeseneder & Hutchinson new species

Description. Size 9.6–18.9 mm. Form elongate ovate or ovate. Colour black or brown with metallic reflections. Head. Clypeus subquadrate to elongate; lateral margins divergent ( Fig. 1 A, detail 1), widest preapically ( Fig. 1 A, detail 2; Fig. 1 C, detail 4); clypeolateral ridge present; anterior margin shallow arcuate to linear ( Fig. 1 A, detail 3); margins gradually inclined to moderate elevations ( Fig. 1 A, detail 4); disc coarsely punctate. Frons bearing low, distinct medial elevation; coarsely punctate. Antenna club enlarged in male, longer than length of antennomeres 2–7. Thorax. Pronotum weakly transverse, trapezoidal ( Fig. 1 C); basomedian margin weakly concave-linear ( Fig. 1 C, detail 1); lateral margins with broad medial angles ( Fig. 1 C, detail 2); disc coarsely punctate ( Fig. 1 C, detail 3). Scutellum base broad, elongate, finely or coarsely punctate. Elytron posthumeral arch weakly sinuate-linear ( Fig. 1 D, detail 1), slightly exposing metacoxa ( Fig. 1 D, detail 2), basal half parallel sided ( Fig. 1 D, detail 3), apical half broadly arcuate to apex ( Fig. 1 D, detail 4); mesepimeron slightly protruding ( Fig. 1 D, detail 5); humeral and apical umbones indistinctly raised ( Fig. 1 D, details 6, 7); sutural costa distinct, bearing two or more distinct narrow costae; disc coarsely punctate, mostly coalesced, eroding costal margins. Mesometasternal process undeveloped, present as low rounded declivous process between mesocoxae ( Fig. 1 F, detail 1). Legs. Protibia bidentate or tridentate, denticles elongate; protarsomeres elongate, simple. Mesotibia unidentate. Mesotarsomeres elongate, simple. Metafemur elongate, anterior margin arcuate. Metatibia elongate, broad or narrow, unidentate ( Figs. 1 H–J); internal spur spatulate in female ( Fig. 1 H, detail 1). Metatarsomeres elongate, simple. Abdomen. Sternites distinctly convex and distended in female ( Fig. 1 E, detail 1). Metasternum sparsely punctate medially, denser rugulose laterally. Pygidium concentrically rugose, female in normal plane ( Fig. 1 E, detail 2) to elevated ( Fig. 1 E, detail 3). Genitalia ( Fig. 2 ). Phallobase 1.5 x length of parameres and widest near base of parameres. Parameres narrowing from base; margin sinuate or parallel, widening near apex; dorsal cleft basally acute-obtuse then attenuate to apex.

Differential diagnosis. The following combination of characters distinguishes Navigator from other Schizorhinini genera. Size 9.6–18.9 mm, colour with metallic reflections, clypeal anterior margin nearly linear, dorsal surfaces coarsely punctate, elytral costae distinct and narrow, male antennal club enlarged, female metatibial internal spur spatulate.

Navigator fossor new combination and N. ruficornis new combination are transferred from the genus Pseudoclithria . Here we distinguish Navigator from the two remaining Pseudoclithria groups, which are the type species P. hirticeps (Macleay, 1871) and all others, which we refer to as Pseudoclithria species. Specimens of Navigator are structurally, and based on our observations also behaviourally, similar to Grandaustralis Hutchinson & Moeseneder, 2013 , Octocollis Moeseneder & Hutchinson, 2012 , and to a lesser degree Tapinoschema Thomson, 1880 . The males of these genera possess greatly enlarged antennal clubs. Both sexes of these genera have a coarsely punctate head, pronotum, and elytra; clypeus with anterior margin sinuate to linear; mesometasternal process undeveloped (except moderately developed in Tapinoschema ); and weakly sinuate to linear posthumeral arch.

Differences to Pseudoclithria hirticeps: Colour with metallic reflections; matt in P. hirticeps . Elytra with two or more distinct, narrow costae; in P. hirticeps with single broad costa. Elytral posthumeral arch sinuate to linear; in P. hirticeps sinuate, exposing abdomen. Mesometasternal process undeveloped; bud-shaped in P. hirticeps . Female pygidium gradually convergent to apex; in P. hirticeps highly transverse with distinctly obtuse apex. Female metatibia internal spur spatulate; in P. h i r t i c ep s elongate, parallel. Male parameres ( Fig. 2 ) narrowing from base, widening to apex; in P. h i r t i ce p s elongate attenuate to apex.

Differences to Pseudoclithria species: colour with metallic reflections; matt in Pseudoclithria species. Pronotum coarsely punctate; finely punctate in Pseudoclithria species. Posthumeral arch sinuate to linear; in Pseudoclithria species. sinuate, often exposing abdomen. Male antennal club greatly enlarged; in Pseudoclithria species. not distinctly enlarged. Elytra with two distinct, narrow costae; in Pseudoclithria species. with single low, wide costa. Legs elongate; in Pseudoclithria species. legs stout. Female metatibial internal spur spatulate; nonspatulate in Pseudoclithria species.

Differences to Octocollis: Size 9.6–18.9 mm; 16–19 mm in Octocollis . Colour with metallic reflections; matt in Octocollis . Clypeus widest preapically; parallel in Octocollis . Pronotum widest basally; in Octocollis widest medially. Elytral costae distinct, narrow; indistinct in Octocollis . Female metatibial internal spur spatulate; unknown in female Octocollis . Parameres narrowing from base, broadening preapically; in Octocollis parameres broad with apical appendage.

Differences to Grandaustralis: Size 9.6–18.9 mm; 18.5–25.5 mm in Grandaustralis . Colour with metallic reflections; matt in Grandaustralis . Elytra with two distinct narrow costae; indistinct in Grandaustralis . Female metatibial internal spur spatulate; parallel in Grandaustralis . Parameres narrowing from base, broadening preapically; in Grandaustralis narrow at base, equal width to apex.

Differences to Tapinoschema: Size 9.6–18.9 mm; 20.3–34.0 mm in Tapinoschema . Colour with metallic reflections; glossy in Tapinoschema . Pronotal shape weakly transverse; in Tapinoschema distinctly transverse. Mesepimeron slightly exposed; in Tapinoschema distinctly exposed. Elytra with two distinct, narrow costae; indistinct in Tapinoschema . Mesometasternal process undeveloped; in Tapinoschema parallel or attenuate elongate. Female metatibia internal spur spatulate; parallel in Tapinoschema . Parameres narrowing from base, broadening preapically; in Tapinoschema narrow at base, broadening to widest at apex.

Species examined: Pseudoclithria hirticeps male, P. mastersii (Macleay, 1871) female, P. maura (Janson, 1874) male and female, P. adusta (Janson, 1889) male, P. dejecta Lea, 1914 male, P. erythroptera Lea, 1914 male (from MNV image), P. anchoralis Lea, 1914 male and female, P. rugosa (Schaum, 1848) male, P. kershawi Lea, 1914 male (from MNV image), seven undescribed Pseudoclithria species (C.H.M. & P.M.H., unpublished data), Tapinoschema digglesii (Janson, 1874) male and female, T. impar ( Macleay, 1863) male and female, T. lacunosa (Janson, 1874) male and female, Octocollis setosus Moeseneder & Hutchinson, 2012 male, Grandaustralis boomerang Hutchinson & Moeseneder, 2013 male and female.

Etymology. Navigator males, in the species where males are known, have enlarged antennae that may have developed to such a size to assist them in locating females. Hence we chose a name for the genus that is descriptive of their searching behaviour. We assume that males, using their enlarged antennae, follow pheromones released by the females and navigate to the source. Navigator is the Latin noun for an entity that directs itself or a vessel over a planned course. The gender of Navigator is masculine.

Remarks. We assign Navigator to the tribe Schizorhinini and, within it, to the subtribe Schizorhinina. In very old specimens of N. fossor and N. ruficornis there is a loss of metallic reflections on all surfaces and only the black or brown base colours are retained (compare Figs. 6 and 9 ).

Figures

FIGURE 1. Navigator characters. A—characters of the head (example N. pixii male): A 1 — margins laterally divergent, A 2 — head widest preapically, A 3 — shallow arcuate to linear anterior margin, A 4 — gradually inclined margins, A 5 — shallow preclypeus, A 6 — cross-section, A 7 — lateral declivity absent. B—characters of the head (example N. ruficornis female): B 1 — lateral declivity present, B 2 — deep preclypeus, B 3 — cross-section, B 4 — lateral declivity present. C—characters of the pronotum (example N. pixii male): C 1 — concave linear basolateral margin, C 2 — broad median angle of lateral margins, C 3 — coarsely punctate disc. D—characters of the elytra (example N. pixii male, except D 9): D 1 — weakly sinuate-linear posthumeral arch, D 2 — slightly exposed metacoxa, D 3 — elytral basal half parallel sided, D 4 — apical half of elytra broadly arcuate to apex, D 5 — slightly protruding mesepimeron, D 6 – 7 — indistinctly raised apical umbone, D 8 — visible pygidium D 9 — pygidium not well visible (example N. ruficornis). E—characters of the female abdomen: E 1 — distinctly convex and distended sternites, E 2 — pygidium in normal plane (example N. ruficornis), E 3 — pygidium in elevated plane (example N. pixii). F—character of the abdomen: F 1 — undeveloped mesometasternal process. G—metacoxa posterolateral angle: G 1 — angulate (examples N. pixii and N. ruficornis), G 2 — broadly arcuate (example N. fossor), G 3 — spinose (example N. interior). H – K: characters of the metatibia: H— Navigator fossor female: H 1 — spatulate internal spur, H 2 — unidentate, H 3 — trispinose apex. I— Navigator ruficornis female: I 1 — large, median denticle, I 2 — trispinose apex. J— Navigator interior female: J 1 — small, median denticle. K— Navigator pixii male: K 1 — unispinose apex. Note: cross-sections in A and B are from clypeal anterolateral angle to clypeolateral margin, not in transverse axis.

FIGURE 2. Navigator male aedeagi. A— Navigator fossor. B— Navigator pixii. C— Navigator ruficornis. Note: male N. interior are unknown.

FIGURE 3. Navigator fossor lectotype, female.

FIGURE 4. Navigator fossor male.

FIGURE 5. Navigator fossor female.

FIGURE 6. Navigator ruficornis lectotype, male. Image © MNHN, A. Mantilleri.

FIGURE 7. Navigator ruficornis male.

FIGURE 8. Navigator ruficornis female.

FIGURE 9. Navigator pixii holotype, male.

FIGURE 13. Navigator interior holotype, female.

FIGURE 14. Navigator habitat. A – D— Navigator fossor (all images near or 10 km west of Menzies, Western Australia): A— Acacia leaf litter and branch thicket. B— Acacia with scattered Grevillea. C—male on leaf litter under Acacia. D—larva in decomposing leaf substrate. E – F— Navigator pixii (images at Boggomoss site BM 03, Queesland): E—collecting locations of adults and larvae. F—accumulations of dead leaves, predominantly from Acacia harpophylla, on the ground under which larvae were found.