Aenigmaphes, Jałoszyński, 2020

Jałoszyński, Paweł, 2020, Aenigmaphes gen. n., a new glandulariine genus of the Australian region (Coleoptera: Staphylinidae: Scydmaeninae), Zootaxa 4731 (3), pp. 439-446 : 440-444

Aenigmaphes gen. n.

Type species: Aenigmaphes papuanus sp. n. (here designated).

Diagnosis. Aenigmaphes differs from all genera of Glandulariini in five apomorphies: the submental region forming an elevated platform demarcated by a step-wise ridge, with hypostomal ridges running along posterior margins of the cardines; the pronotum with one pair of adjacent antebasal pits at middle, connected by a longitudinal groove; the basisternum demarcated posteriorly by a carina; the inner (adcoxal) portion of each hypomeron conspicuously narrow; and the posterior margin of each mesocoxal rest demarcated by a step-wise ridge (not carina), which extends laterad and is bent posterad to connect with lateral metaventral margin far behind mesocoxae. Additionally, Aenig- maphes is characterized by a set of synapomorphies, which, separately or in a different combination, are known in other Glandulariini : antenna with dimerous club; head round, with eyes situated closer to mandibular bases than to posterior margin of vertex; frons in front of eyes distinctly constricted; occipital constriction only slightly narrower than vertex; submentum lacking lateral sutures; tempora with dense setae, but lacking thick bristles; pronotum near- ly circular, lacking lateral and sublateral carinae; sides of pronotum and hypomera lacking thick bristles; mesocutel- lum not exposed between elytral bases, subtriangular, not elongate; procoxal cavities closed by posterolateral lobes of prosternum firmly fused with postcoxal region of hypomera; hypomeral ridges incomplete, anteriorly obliterated; notosternal sutures largely obliterated; each elytron with one large, deep and setose basal fovea, lacking humeral callus, with two short and diffuse basal carinae originating from humerus and from lateral margin of basal elytral fovea; mesoventrite with prominent mesocoxal projections, short and diffuse asetose impressions functioning as procoxal rests; mesoventral intercoxal process carinate, strongly elevated anteriorly, posteriorly gradually broaden- ing and flattening, fused with metaventrite; metaventral intercoxal process narrow, composed of a pair of slender spines; aedeagus with symmetrical median lobe and nearly symmetrical, simple endophallus, parameres not fused with walls of median lobe, with apical setae.

Description. Body ( Fig. 1 ) elongate, with distinct constrictions between head and prothorax and between prothorax and elytra; sparsely setose.

Head capsule ( Figs 1–2, 4 ) divided into a short ‘neck’ region retracted into pronotum and short and round anterior part; occipital constriction only slightly narrower than vertex; vertex ( Fig. 2 ; vt) and frons ( Fig. 2 ; fr) confluent, weakly convex and together about as long as broad, anterior margin of frons subtrapezoidal, sides in front of eyes constricted, posterior margin of vertex rounded, not bulging posterodorsad and forming a diffuse ridge. Eyes closer to mandibular basis than to posterior margin of vertex, composed of a small number of large ommatidia; antennal insertions narrowly separated; tempora and vertex evenly, strongly rounded, so that border between temple and posterior margin of vertex is not marked. Head with long and dense setae on tempora, genae and postgenae, but lacking thick bristles. Gular plate ( Fig. 4 ; gp) large, with indistinct gular sutures; posterior tentorial pits ( Fig. 4 ; ptp) slightly in front of transverse impression demarcating ‘neck’ region ventrally, round and small; submental region forming broad and slightly elevated crescent-shaped area demarcated by a step-wise ridge, devoid of punctures and setae; hypostomal ridges ( Fig. 4 ; hr) diffuse, strongly bent mesad and running along posterior margins of cardines, not connected at middle. Mentum subtrapezoidal; prementum small, with narrowly separated bases of labial palps, palpomere II longest. Maxillae generalized, as in most Glandulariini ; maxillary palpomere I short, slightly elongate, II long, clavate, III large but slender, palpomere IV slender, nearly rod-like, with subcylindrical apical portion.

Antennae ( Figs 1, 3 ) moderately long, slender, with large dimerous club, antennomere IX only slightly enlarged; all antennomeres covered with sparse, long setae.

Pronotum ( Figs 1–2 ) in dorsal view nearly circular and strongly convex, anterior and lateral margins confluent, so that anterior corners not marked, posterior corners weakly marked, strongly obtuse-angled; posterior margin weakly bisinuate. Pronotum lacking lateral and sublateral carinae, with antebasal median longitudinal groove ( Fig. 2 ; lg) and a pair of small antebasal pits ( Fig. 2 ; abp), which are confined in proximal portion of the groove and under light microscope appear as one. Sides of pronotum with long setae posteriorly, but lacking thick bristles.

Prosternum ( Figs 4–5 ) with basisternal portion ( Fig. 5 ; bst) much shorter than coxal part and demarcated by arcuate transverse carina; prosternal process developed as diffuse, weakly elevated subtriangular area not separating procoxae; notosternal sutures ( Figs 4–5 ; nss) largely obliterated, visible only just in front of procoxae and at anterior sternal margin; procoxal cavities closed by posterolateral lobes of prosternum that are fused with postcoxal portions of hypomera; hypomeral ridges ( Figs 4–5 ; hyr) incomplete, anteriorly obliterated, demarcating conspicuously narrow inner (adcoxal) region of hypomeron.

Mesonotum (not shown) with subtriangular scutellar shield about as long as broad, not exposed between elytral bases.

Elytra ( Figs 1–2 ) oval and with strongly reduced humeri, each with one large and deep basal elytral fovea ( Fig. 2 ; bef) filled with setae; and two faint carinae: one extending posterolaterad from lateral margin of basal elytral fovea, and one vestigial running from humerus; apices of elytra rounded together.

Mesoventrite ( Figs 6–7 ) with mesoventral intercoxal process ( Figs 6–7 ; msvp) carinate, anteriorly narrow and strongly elevated, posteriorly gradually broadening and flattening, anteriorly reaching anterior mesoventral margin, posteriorly fused with metaventrite. Lateral impressions functioning as procoxal rests ( Fig. 6 ; pcr) short, asetose, with all margins well-defined, separated at middle. Mesoventrite lacking lateral foveae, with prominent mesocoxal projections. Mesanepisternum and mesepimeron with conspicuously long and dense setae well-visible in dorsal view ( Figs 1–2 ).

Metanotum (not shown) strongly reduced and with indistinct alacristae.

Hind wings absent.

Metaventrite ( Figs 6–7 ) about as long as broad, strongly broadening posteriorly; posterior margins of meso- coxal rests demarcated by a step-wise diffuse ridge (not carina) which is strongly bent posterolaterad; posterior margin strongly concave at each metacoxa, with metaventral intercoxal process ( Figs 6–7 ; mtvp) composed of a pair of slender spines narrowly separating metacoxae. Metanepisterna and metepimera narrow, inconspicuous.

Metendosternite (= metafurca) ( Fig. 6 ) with short and broad stalk and divergent lateral furcal arms ( Fig. 6 ; lfa) with adjacent bases (V-shaped).

Legs moderately long and slender; pro- and mesocoxae oval, metacoxae strongly transverse and laterally reach- ing margins of metaventrite; all trochanters short and subtriangular; all femora distinctly clavate; tibiae slightly broadening distad; tarsi moderately slender.

Abdominal sternites ( Fig. 7 ) unmodified, suture between sternites VII and VIII barely discernible.

Aedeagus ( Fig. 8 ) elongate, with symmetrical median lobe and nearly symmetrical tubular endophallus, parameres slender, with apical setae.

Distribution and composition. Aenigmaphes is represented by one nominal species known to occur in eastern New Guinea; females from Sulawesi representing another species have been seen.

Etymology. The name Aenigmaphes combines the prefix aenigma - (Latinized Greek ainigma, a riddle, mystery), and the stem - phes derived from - raphes, commonly used in many generic names of Glandulariini . Gender masculine.

Remarks. The tribe Glandulariini currently comprises 83 genera (including Aenigmaphes ), of which 74 are extant. Aenigmaphes differs from all of them in five apomorphies: the submental region forming an elevated platform demarcated by a step-wise ridge which is not continuous with the hypostomal ridges; the pronotum with one pair of adjacent antebasal pits at middle, connected by a longitudinal groove; the basisternum demarcated posteriorly by a carina; the inner (adcoxal) portion of each hypomeron conspicuously narrow; and the posterior margin of each mesocoxal rest demarcated by a step-wise, rounded ridge, which extends laterad and is bent posterad to connect with the lateral metaventral margin far behind mesocoxae.

Thirty-one genera are known to occur in Eurasia and Australia (incl. Aenigmaphes ). The Australian Psepharobius King, 1864 is not possible to identify because of an unclear original description and an unknown depository of the type specimens of its sole species. Among the remaining genera, nine ( Leptoderoides Croissandeau, 1898 ; Neu- raphes Thomson, 1859; Palaeoscydmaenus Franz, 1975 ; Rutaraphes Jałoszyński, 2015b ; Scydmaenilla King, 1864 ; Scydmoraphes Reitter, 1891 ; Siamites Franz, 1989 ; Stenichnodes Franz, 1966 ; and Stenichnus Thomson, 1859 ) are characterized by the submental region demarcated laterally by sutures, which are absent in Aenigmaphes . Euconnus , Kangarooconnus Jałoszyński, 2017 (in Jałoszyński & Newton 2017), and Leascydmus Jałoszyński, 2014b have the metacoxae separated by a variously broad metaventral intercoxal process, which never bears a pair of spines (in Aenigmaphes the metacoxae are narrowly separated by a pair of long spines). Aenigmaphes has largely obliterated notosternal sutures, a character that is clearly different (i.e., complete or nearly complete sutures) in Bellendenker Jałoszyński, 2017 ; Heterotetramelus Franz, 1971 ; Himaloconnus Franz, 1979 ; Horaeomorphus L.W. Schaufuss, 1889 ; Loeblites Franz, 1986 ; Napoconnus Franz, 1957 ; Schuelkelia Jałoszyński, 2015c ; Sciacharis ; Scydmaenozila Jałoszyński, 2014b ; Scydmepitoxis Jałoszyński, 2014d ; Spinosciacharis Jałoszyński, 2014b ; and Syndicus Motschulsky, 1851 . This leaves five genera ( Afroeudesis Franz, 1963 ; Elacatophora L.W. Schaufuss, 1884 ; Lepto- charis Reitter, 1887; Microscydmus Saulcy & Croissandeau, 1893 ; and Penicillidmus Jałoszyński, 2014c ) that are similar to Aenigmaphes in having the submentum not demarcated laterally by sutures, the metacoxae contiguous or, if subcontiguous, separated narrowly by a pair of slender spines; and incomplete notosternal sutures ( Leptocharis in Jałoszyński (2015c) was illustrated with complete sutures; but a SEM re-examination of the same species revealed that notosternal sutures are marked only at the anterior sternal margin). Apart from the aforementioned autapomorphies, Aenigmaphes differs from each of them in several easily observable characters. Afroeudesis , in the discussed regions inhabiting only sub-Himalayan areas, has a triangular, elevated ‘platform’ on the frons and vertex divided by a longitudinal median groove, a bell-shaped pronotum, complete hypomeral ridges, a parallel-sided prosternal process, and a massive subtriangular anterior metaventral process (in Aenigmaphes the ‘platform’ on the head is absent, the pronotum is nearly circular, the hypomeral ridges incomplete, the prosternal process barely discernible as diffuse, subtriangular elevation, and the metaventrite lacks the anterior process). In the Oriental Elacatophora , the gular plate between the occipital constriction and submentum is narrow, elongate and laterally clearly demarcated from genae and postgenae; the procoxal cavities situated closer to anterior than posterior sternal margin; the hypomeral ridges absent, and the pronotum subconical (in Aenigmaphes , the gular plate does not have an elongate, demarcated anterior portion; the procoxal cavities are behind middle of the prosternum; the hypomeral ridges in- complete but present; and the pronotum almost circular). In the West Palaearctic Leptocharis , the antennal clubs are clearly trimerous; the pronotum elongate, bell-shaped; and the lateral margins of metacoxae are broadly separated from the lateral margins of the metaventrite (in Aenigmaphes , the antennal clubs are dimerous, with only slightly enlarged antennomere IX; the pronotum is almost circular; and the lateral margins of the metacoxae connect with the lateral margins of the metaventrite). In the cosmopolitan Microscydmus , the antennal clubs are clearly trimerous; the hypomeral ridges complete; and the lateral pronotal antebasal pits are connected by a transverse groove (only rarely indistinct or absent) (in Aenigmaphes , the antennal clubs are dimerous, with only slightly enlarged antennomere IX; the hypomeral ridges incomplete; and the pronotum lacks lateral pits and a transverse groove). Finally, in the Australo-Oriental Penicillidmus (with many new Oriental species awaiting description and some having been misplaced in Microscydmus ; Jałoszyński, in prep.), the submental region is demarcated by longitudinal lateral carinae, each with a transverse lateral arm extending toward eye; the pronotum bears a pair of conspicuous postero- lateral penicilli; the hypomeral ridges are complete; and the basal elytral foveae are asetose (in Aenigmaphes , the submental region is not demarcated by carinae; the pronotal penicilli are absent; the hypomeral ridges incomplete; and the basal elytral foveae are filled with setae).

Aenigmaphes papuanus sp. n.

( Figs 1–7 )

Type material. Holotype: PAPUA NEW GUINEA (Oro Prov.): ♂, two labels: “PAPUA / nr. Kokoda, c. 500m / 1.vi.1972, R.W.Taylor / rainfor. berlesate” [white, printed], “ AENIGMAPHES / papuanus m. / P. Jałoszyński, 2019 / HOLOTYPUS” [red, printed] ( MHNG).

Diagnosis. As for genus.

Description. Body of male ( Fig. 1 ) moderately slender, strongly convex, brown with slightly lighter appendages, setae yellowish; BL 0.69 mm.

Head ( Fig. 2 ) broadest at large, strongly convex eyes, HL 0.13 mm, HW 0.13 mm; frons and vertex confluent, vertex strongly convex posteriorly and slightly flattened anteriorly, frons flattened; tempora shorter than eyes in dor- sal view, strongly convergent mesad and posteriorly confluent with posterior margin of vertex; each eye composed of three large and strongly convex ommatidia. Punctures on vertex and frons superficial and barely discernible; se- tae short, sparse, recumbent, except for groups of long and dense setae on tempora. Antennae ( Fig. 3 ) slender, AnL 0.30 mm; antennomeres I and II each strongly elongate, III–VIII each slightly to distinctly elongate, IX distinctly longer and slightly broader than VIII, slightly elongate, X strongly enlarged, slightly elongate, with well-defined distal subconical portion devoid of setae; XI about as broad as X but slightly longer, oval with flattened base.

Pronotum ( Figs 1–2 ) broadest slightly behind middle; PL 0.19 mm, PW 0.20 mm. Anterior margin and lateral margins in anterior 2/3 strongly, nearly evenly rounded, sides in posterior third slightly sinuate and strongly convergent toward base. Antebasal longitudinal median groove broadest posteriorly and gradually narrowing anterad, not reaching middle of pronotum. Punctures on pronotal disc similar to those on frons and vertex, inconspicuous; setae short, sparse, nearly recumbent, except for posterolateral setae, which are long and directed posterad.

Elytra ( Figs 1–2 ) together oval, broadest distinctly behind middle; EL 0.38 mm, EW 0.28 mm, EI 1.36; elytra from the broadest site more strongly narrowing anterad than posterad. Punctures and setae on elytra similar to those on pronotum. Hind wings absent.

Legs moderately long and slender; unmodified.

Aedeagus ( Fig. 8 ) strongly elongate; AeL 0.13 mm; median lobe weakly sclerotized, in ventral view oval with subtrapezoidal, abruptly narrowed apical region, endophallus with long median tubular structure broadest near base; parameres long and slender, each with one thick and long apical seta.

Female. Unknown.

Distribution. Eastern New Guinea.

Etymology. After the country name.

Figures

FIGURES 1–8. Aenigmaphes papuanus gen. & sp. n., holotype male. Dorsal habitus (1); head, pronotum and elytral base in dorsal view (2); distal portion of right antenna in dorsal view (3); head, prothorax and anterior portion of mesothorax in ventral view (4); prothorax in ventral view (5); pterothorax in ventral view (6); pterothorax and abdomen in ventral view (7); aedeagus in ventral view (8). Abbreviations: abp, antebasal pit; bef, basal elytral fovea; bst, basisternum; fr, frons; gp, gular plate; hr, hypostomal ridge; hyr, hypomeral ridge; lfa, lateral furcal arm; lg, longitudinal groove; msvp, mesoventral intercoxal process; mtvp, metaventral intercoxal process; nss, notosternal suture; pcr, procoxal rest; ptp, posterior tentorial pit; vt, vertex.