Apoderiger Wasmann, 1897

Hlaváč, Peter, 2025, The Pselaphinae (Coleoptera: Staphylinidae) of Madagascar. VIII. Revision of the myrmecophilous clavigerine genus Apoderiger Wasmann, 1897, European Journal of Taxonomy 981, pp. 76-95 : 79-83

Genus Apoderiger Wasmann, 1897

Apoderiger Wasmann, 1897: 263 .

Type species: Apoderiger cervinus Wasmann , by monotypy.

Soalala Dajoz, 1982: 512 . Type species: Soalala spinosa Dajoz , by original designation; synonymy in Besuchet, 2008: 65.

Apoderiger – Jeannel 1954: 312 (redescription); 1960: 202 (in key); 1960: 203. — Célis 1970: 248 (diagnosis, key to species). — Besuchet 2008: 65 (synonymy of Soalala ).

Diagnosis

Head elongate, at least twice as long as wide; temples shorter than frontal rostrum; lacking frontal foveae, with pair of minute dorsal tentorial pits, situated behind eyes. Neck region subcylindrical, long, about as long as or slightly shorter than posterior part of head capsule, separated from head capsule by deep occipital constriction, partly retracted into prothorax. Antenna trimerous; terminal antennomere very long, dilated and curved distally, its apex truncate, with dense short and long setae. Pronotum transverse, clearly wider than long, lacking antebasal and lateral foveae. Elytra more than 1.50 × as wide as long; lacking basal foveae; humeri strongly prominent; posterior margin of elytron lacking trichomes. Abdomen with composite tergite convex, lacking impressions, keels and lacking trichomes; three paratergites of composite tergite present, first paratergite in anterior portion with trichome; posterior margin of composite tergite with pair of small, bump-like, wide-distant or with pair of long, triangular, short-distant projections. Legs long and slender; femur lacking interlocking ridge; mesotibia differently modified in pre or apical portion. Aedeagus elongate, slender, 2.5–3.0× as long as wide; basal bulb well-separated from distal lobe; endophallus with or lacking sclerites; dorsal diaphragm round or elliptical.

Description

BODY ( Fig.1 ). Yellowish-brown, elongated, more about 2.5 × as long as wide. Length 1.4–2.2 mm.

HEAD. Elongate, at least twice as long as wide, widest at level of eyes; rostrum narrow, rounded at anterior margin; eyes oval, slightly prominent, situated slightly behind midpoint of head capsule; temples shorter than frontal rostrum, behind eyes slightly convergent posteriad; lacking frontal foveae, with pair of minute dorsal tentorial pits, situated behind eyes; clypeus partly visible on sides. Neck region subcylindrical, long, about as long as or slightly shorter than posterior part of head capsule, separated from head capsule by deep occipital constriction, partly retracted into prothorax, with well-defined gular plate ( Fig. 2A ); posterior tentorial pits ( Fig. 2A ; ptp = gular foveae of Chandler 2001) small, circular, well-separated, situated in front of transverse impression demarcating neck region ventrally; pre-tentorial gular-submental region elongate, subrectangular and smooth.

ANTENNA. Trimerous ( Fig. 2C–E ), semi-circular in cross-section, very long, exceeding posterior margin of pronotum; scape slightly longer than pedicel, both small, subrectangular; terminal antennomere (flagellomere) very long, more than 10 × as long as wide, dilated distad and variably shaped, curved distally, its apex truncate, with dense short and long setae.

MOUTHPARTS. Rudimentary but well-developed, completely hidden in transversally elliptical bucal cavity ( Fig. 2A–B ); labium with transverse, sub-rectangular mentum ( Fig. 2A–B ), anterior margin of mentum slightly rounded, its anterior half with long setae placed in two rows, lacking ligula. Maxilla reduced, with large, hemispherical cardo ( Fig. 2B ); basistipes ( Fig. 2B ) minuscule, with one seta; galea and lacinia atrophied. Maxillary palpi ( Fig. 2B ) reduced to one palpomere. Mandibles ( Fig. 2B ) ovaly projecting on outer portion. Labrum ( Fig. 2B ) transverse with almost straight anterior margin; anteroventral margin with some peg-like sensilla ( Fig. 2B ); clypeus ( Fig. 2B ) large, transverse, with rounded anterior margin which is bearing bunch of long setae.

PRONOTUM. Transverse, clearly wider than long, about half of length of head; lacking squamouse setae; lateral margin rounded, in anterior and posterior half convergent; lacking antebasal and lateral foveae; lacking sulci or carinae.

PROSTERNUM ( Fig. 3A ). Laterally fused with hypomera; basisternal region longer than coxal region, with sparse setae, with pair of small, widely separated asetose lateral procoxal foveae ( Fig. 3A ; lpcf = term of Chandler 2001; in fact, these foveae are situated on prosternum, anterad procoxal cavities), median procoxal fovea absent; prosternal process ( Fig. 3A ) rounded, not separating procoxae. Hypomera divided by incomplete hypomeral ridges ( Fig. 3A ) into narrow, elongate inner hypomeral region ( Fig. 3A ) and broad, smooth outer hypomeral region ( Fig. 3A ), latter with shallow hypomeral groove ( Fig. 3A ).

MESONOTUM AND METANOTUM. Not studied.

MESOVENTRITE. Fused with metaventrite, with sparse setae being denser on metaventral disc, lacking foveae; mesocoxae separated, width of isthmus about half of diameter of mesocoxal cavity; mesoventral and anterior metaventral process subequal in length, truncate; disc of metaventrite slightly convex in anterior part, declining to posterior margin, lacking projection, patch of trichome-like setae or strong median longitudinal keel; metaventral posterior process ( Fig. 3A ) wide, short, with straight posterior margin or long, semitriangular, with pointed and setose projecting posterior part exceeding part of abdominal sternites.

ELYTRA. 1.60–1.70× as wide as long, 1.50–1.70 × as long as pronotum, with unevenly distributed short setae; lacking basal foveae; with or without discal and sutural striae; postero-lateral corner of elytron obliquely bevelled mesad, lacking projection; humeri strongly prominent; posterior margin of elytron lacking trichomes.

ABDOMEN. With composite tergite convex, lacking impressions or keels, lacking trichomes; three paratergites of composite tergite present, first paratergite in anterior portion with trichome; posterior margin of composite tergite with pair of small, bump-like, wide-distant or with pair of long, triangular, short-distant projections.

ABDOMEN ( Fig. 3B ). With first visible sternite (III) narrow, more than 6 × as short as second visible sternite (IV) which is almost twice as long as third (V); all sternites simple, lacking any modification.

LEGS. Moderately long and slender; femur lacking interlocking ridge; mesotibia differently modified in pre or apical portion, sometimes with mesotibial preapical tooth ( Fig. 3C ); tarsomere 1 minuscule ( Fig. 3C ), 2 much longer, 3 considerably longer than 2, with subtriangular distal lamella ( Fig. 3C ).

AEDEAGUS ( Fig. 4A–J ). Elongate, slender, 2.5–3.0× as long as wide; basal bulb well-separated from distal lobe, ratio length of basal bulb /length of distal lobe variable 0.9–2.4; endophallus with or lacking sclerites; dorsal diaphragm round or elliptical.

Sexual dimorphism

Females always with short, wide posterior metaventral process, mesotibia always simple, lacking any kind of modification.

Host ant

Paratrechina amblyops rubescens (Forel, 1892) is the only host ant known so far for the genus.

Distribution

The centre of the distribution of the genus Apoderiger is the eastern part of central Madagascar, where four species are present, A. banari sp. nov., A. sikorai sp. nov. in the massif Anjozorobe – Andasibe, A. cervinus on the Imerina Plateau and one, the most southern record of an undescribed species, in the Ranomafana National Park. There are three isolated species located more to the north, A. spinosus on the western coast, Soalala district, A. grandis sp. nov. on northeastern part, Manongarivo Special Reserve and A. torticornis in Antongil Bay, north-eastern part ( Fig. 5 ).

Remarks

Two well-defined groups of species can be recognized within the genus which are readily separated by the different structure of a pair of projections on the posterior margin of the composite tergite. The first group, containing A. spinosus ( Dajoz, 1982) and A. sikorai sp. nov., has posterior margin of composite tergite with pair of small, bump-like, wide-distant projections and strongly curved distal portion of terminal antennomere. The second group, with A. torticornis , A. grandis sp. nov. and A. banari sp. nov., has posterior margin of composite tergite with pair of long, triangular, short-distant projections which are or not exceeding posterior margin of abdomen and slightly curved distal portion of terminal antennomere. Except A. cervinus , because of unknown male, the remaining species of the genus can be separated using the following key.

Key to males

( Apoderiger cervinus is missing in the key because the male of this species is unknown).

1. Posterior margin of composite tergite with pair of small, bump-like, wide-distant projections ( A. spinosus species group) .............................................................................................................. 2

– Posterior margin of composite tergite with pair of long, triangular, short-distant projections ( A. torticornis species group) ........................................................................................................... 3

2. Small species, about 1.40 mm long; apex of mesotibia with inner projection ................................... ................................................................................................................... A. spinosus ( Dajoz, 1982)

– Large species, about 1.70–1.85 mm long; apex of mesotibia lacking inner projection, only with small preapical tooth ( Fig. 3C ) .............................................................................. A. sikorai s p. nov.

3. Triangular paired projections on posterior portion of composite tergite shorter, not exceeding posterior margin of abdomen; posterior subtriangular metaventral process exceedingly over first visible sternite (III) ................................................................................................ A. banari sp. nov.

– Triangular paired projections on posterior portion of composite tergite longer, clearly exceeding posterior margin of abdomen; posterior metaventral process wide, short, with almost straight posterior margin, not exceedingly over first visible sternite (III) ..................................................... 4

4. Elytra with discal and sutural striae; large species, about 2.2 mm long; head less than 1.60 × as long as pronotum .......................................................................................................... A. grandis sp. nov.

– Elytra lacking discal and sutural striae; small species, about 1.8–1.9 mm long; head more than 1.75 × as long as pronotum ............................................................................... A. torticornis Jeannel, 1960

Figures

Fig. 1.Dorsal habitus of male.A. Apoderiger torticornisJeannel, 1960,holotype (MNHN).B. Apoderiger banari sp. nov., holotype (PCPH).

Fig. 2. Apoderiger sikorai sp. nov., paratype, ♂ (PCPH). A. Head in ventral view. B. Mouth part. C–D. Antenna.E. Apoderiger torticornis Jeannel, 1960, holotype, ♂ (MNHN), antenna. Abbrevations: bst = basistipes; cd = cardo; cl = clypeus; gp = gular plate; lb = labrum; md = mandible; mn = mentum; mxp = maxillary palpi; ps = peg-like sensilla; ptp = posterior tentorisl pits.

Fig. 3. Apoderiger sikoraisp. nov., paratype,♂ (PCPH).A. Prosternum and metaventrite.B. Metaventrite and abdomen. C. Distal part of tibia and tarsus. Abbrevations: amtp = anterior metaventral process; ihy = inner hypomeral region; hyr = hypomeral ridges; hyg = hypomeral groove; lpcf = lateral procoxal fovea; msvp = mesoventral process; mtvp = posterior metaventral process; ohy = outer hypomeral region; psp = prosternal process; pst = prosternum; sbl = tarsal subapical tooth; tpat = tarsal preapical tooth; III–IX = visible tergites.

Fig. 4. Dorsal and lateral view of aedeagus. A–B. Apoderiger torticornis Jeannel, 1960, lectotype (MNHN). C–D. Apoderiger sikorai sp. nov., paratype (NMW). E–F. Apoderiger spinosus (Dajoz, 1982), holotype (MNHN).G–H. Apoderiger banari sp. nov., holotype (PCPH).I–J. Apoderiger grandis sp. nov., holotype (MHNG).

Fig. 5. Distribution map of Apoderiger Wasmann, 1897.