Anaulacaspis, GANGLBAUER, 1895

Assing, Volker, 2016, Revision of the Anaulacaspis species of the Palaearctic region (Coleoptera: Staphylinidae: Aleocharinae), Beiträge Zur Entomologie = Contributions to Entomology 66 (2), pp. 201-255 : 203-206

3.1 The genus Anaulacaspis

Redescription: Body of rather small size; body length 1.6–3.3 mm; length of forebody 0.8–1.5 mm. Coloration variable. Habitus as illustrated in Fig. 211 .

Head more or less distinctly transverse, with or without sexual dimorphism, in male often depressed or shallowly impressed in median or postero-median portion of dorsal surface and/or with more distinct punctation than in female; posterior constriction approximately onethird as broad as maximal head width; ventral aspect of head smooth; gular sutures broadly separated. Eyes rather large, slightly shorter, approximately as long as, or longer than postocular region in dorsal view. Antenna of moderate length, weakly to distinctly incrassate apically. Labrum strongly transverse, shape and chaetotaxy as in Fig. 3 . Right mandible with very obtuse, sometimes indistinct molar tooth in the middle; left mandible without molar tooth. Maxilla and labium as in Figs 1–2 .

Pronotum more or less distinctly transverse, broadest at or near anterior angles, tapering posteriad; posterior angles obtuse, moderately marked; along midline rarely with, usually without weakly pronounced median sulcus of reduced length posteriorly, this sulcus (if present) anteriorly not, or only slightly, extending beyond middle of pronotal length (never as deep and long as in Falagria ); with or without sexual dimorphism: in male often with median depression, impression, or sulcus in posterior half, and/or with more distinct punctation than in female. Prosternite strongly transverse, in the middle elevated, but not carinate.

Elytra of variable length and width; scutellum without sulcus, flat, and usually densely punctate, in one species ( A. inexpectata ) with coarse, irregularly longitudinal rugae. Process of mesoventrite broad and apically obtusely truncate, reaching approximately halfway between mesocoxalcavities; mesocoxalcavitiesnotmarginedposteriorly; metaventrite long, much longer than mesoventrite. Metatarsomere I elongate, at least approximately as long as the combined length of metatarsomeres II–IV.

Abdomen broadest at tergite V; tergites III–V with more or less distinct anterior impressions, impression of tergite V as deep as those of tergites III–IV, or shallower; anterior impressions of tergites III–V smooth and impunctate, finely punctate, or coarsely and densely punctate; sternites III–V constricted anteriorly; punctation of posterior tergites finer and sparser than that of anterior tergites, often also finer and sparser on posterior portions than on anterior portions of tergites; tergite VII with palisade fringe; tergite VIII anteriorly with a more or less pronounced median excision (e.g., Figs 4–9 ) (exception: A. inexpectata ), with or without weakly pronounced sexual dimorphism; posterior margin of tergite VIII with thin (unmodified) or with more or less distinctly modified marginal setae; sternite VIII with more or less pronounced sexual dimorphism.

♂: posterior margin of sternite VIII more or less distinctly produced in the middle; median lobe of aedeagus of variable size (in relation to body size) and usually of simple structure; paramere distinctly divided into paramerite and condylite; condylite without distinct velum, much narrower and shorter than the paramerite; apical lobe of paramerite short.

♀: posterior margin of sternite VIII broadly convex, often weakly concave in the middle; spermatheca minute, short, and comma-shaped ( Figs 186 , 210 ) (exception: A. inexpectata ).

Comparative notes: Except for A. inexpectata , Anaulacaspis is distinguished from all other genera of Falagriini recorded from the Palaearctic region by the median excision of the anterior margin of tergite VIII and by the minute comma-shaped spermatheca. In addition, it differs from similar falagriine genera as follows: from Falagria by the absence of a long and deep median sulcus on the pronotum and on the scutellum, as well as by the chaetotaxy of tergite VIII ( Falagria : whole posterior margin with a very dense fringe of short modified setae); from Falagrioma by the absence of a long and deep median sulcus on the pronotum, by the different punctation of the elytra ( Falagrioma : punctation conspicuously dense in antero-median portion), and by the chaetotaxy of tergite VIII ( Falagrioma : posterior margin with a dense fringe of moderately short modified setae); from Cordalia by a less globulous pronotum and by the chaetotaxy of tergite VIII ( Cordalia : tergite VIII conspicuously modified, at least posterior portion with dense fringes of fur-like long pubescence).

All other falagriine genera known from the Palaearctic region are readily distinguished from Anaulacaspis by different habitus and/or size alone.

Species groups: The speciose A. nigra group includes A. nigra , A. caucasica , A. pseudonigra , A. reticulata , A. libanotica , A. sinuata , A. nigerrima , A. persica , A. truncata , A. convexa , A. eminens , and A. . It is characterized by small body size, mostly dark coloration (exception: A. persica and allied species, A. gratilla ), in most species a more or less distinct, but generally weakly pronounced sexual dimorphism of the head and/or the pronotum, a deep and rather narrow median excision of the anterior margin of tergite VIII, the derived chaetotaxy of tergite VIII (postero-laterally with a more or less pronounced cluster of dense long thin setae on either side; posterior margin with unmodified marginal setae), and a small median lobe of the aedeagus (in relation to body size). At least the postero-lateral clusters of setae of tergite VIII and the deep median excision of the anterior margin of tergite VIII most likely represent synapomorphies constituting the monophyly of this group. Within the A. nigra group, the species allied to A. persica ( A. persica , A. truncata , A. convexa , A. eminens ) form a distinct monophylum constituted by the modified tergite VIII (posterior margin strongly convex or conspicuously projecting the middle).

Thirteen species are assigned to the A. naevula group, some of them only tentatively: A. naevula , A. seclusa , A. desertorum , A. cristata , A. excisa , A. pamphylica , A. flavomarginata , A. nigrina , A. laevigata , A. iberica , A. beijingensis , A. taiwanica , and A. schuelkei . They share the absence of distinct postero-lateral clusters on tergite VIII, unmodified marginal setae at the posterior margin of tergite VIII (exceptions: A. pectinata , A. gilva ), and an often large median lobe of the aedeagus (in relation to body size). Moreover, the median excision of the anterior margin of tergite VIII is shallower and broader than in the A. nigra group, the posterior margin of the male sternite VIII is more or less obtusely pointed in the middle (not distinctly produced), and the posterior margin of the female sternite VIII is usually weakly concave in the middle. Anaulacaspis taiwanica (shape and chaetotaxy of tergite VIII sexually dimorphic) and A. schuelkei (male sternite VIII distinctly produced posteriorly) are only tentatively assigned to this group. There is little doubt that A. laevigata and A. iberica represent sister species, as can be inferred from their highly similar external and secondary sexual characters. They form a distinct lineage together with A. nigrina , with which they share an extremely fine and sparse punctation of the forebody and the absence of a sexual dimorphism of the head and pronotum.

The two species of the A. gilva group, A. gilva and A. pectinata , in some respects resemble those of the A. naevula group, but are distinguished by the absence of a sexual dimorphism of the head and pronotum, extremely fine and rather sparse punctation of the forebody, by a distinct comb of modified setae at the posterior margin of tergite VIII, and by a conspicuously derived morphology of the aedeagus (ventral process very long and slender both in lateral and in ventral view; internal sac with a long dark structure).

The monophyly of the A. formosa group, which contains only A. formosa and A. elegans , is constituted by the synapomorphically modified chaetotaxy of tergite VIII (posterior margin with distinctly modified short and stout setae, Figs 197 , 219 ). In other respects both species are similar to the representatives of the A. naevula group. Whether this lineage is nested within the A. naevula group or represents a distinct lineage is uncertain. Until this question is clarified, the A. formosa group is regarded as a separate lineage.

The monotypical A. beesoni group is distinguished from all other Palaearctic representatives of the genus by the conspicuously derived chaetotaxy of tergite and sternite VIII (postero-laterally with clusters of modified, apically dilated setae, Fig. 223 ).

The generic assignment of A. inexpectata is doubtful. Though similar in habitus, punctation, the shape of the pronotum, the morphology of the scutellum, and numerous other characters, it lacks two presumable synapomorphies of other Anaulacaspsis species (median excision of the anterior margin of tergite VIII; minute and comma-shaped spermatheca) and additionally differs from all other Anaulacaspis species by a conspicuously rugose scutellum. However, since the possibility that these characters represent derived characters (autapomorphies) cannot be ruled out and since there are no evident synapomorphies suggesting that it should belong to any other described genus of Falagriini , the species is tentatively retained in Anaulacaspis .

Intraspecific variation and polymorphism: Many species are subject to remarkable intraspecific variation of coloration and also size. A pronounced polymorphism of the shape and length of the elytra (and probably also of the length of the hind wings) was observed for Anaulacaspis nigra and A. formosa . In the former, specimens from populations in West and Central Europe usually have short and relatively narrow elytra, whereas those from Southeast Europe and Asia tend to have distinctly longer and broader elytra. Similarly, material of A. formosa from Spain is generally characterized by short and narrow elytra, while those of specimens from North Africa tend to be distinctly longer and broader. However, intermediate forms were observed in Morocco and Algeria, and Moroccan populations may be composed of both longand short-winged morphs.

Remarkable intraspecific variation was not only observed for external, but also for the male primary and secondary sexual characters. This is particularly true of the aedeagus of A. nigra , which may considerably vary in size. Moreover, the semi-transparent median carina at the base of the ventral process may be pronounced (most populations) to almost missing (populations in Corfu, the Pelopónnisos, and in Albania). Finally, while the male tergite VIII is weakly concave in most populations, it may be strongly concave in material from Bulgaria.

Identification: Disregarding A. nigra , which is the sole representative of the genus in much of Europe, more than half of the examined specimens were either misidentified, or they had been identified based on a misinterpretation of the respective species. Consequently, previous literature records are mostly unreliable, particularly those from regions where several species are present.

In view of the pronounced intraspecific variation of characters such as the coloration, size, modifications of the male head and pronotum, and the length of the elytra on the one hand, and often low interspecific variation not only of external characters but also of the spermatheca on the other, the best character for a reliable identification is the shape of the median lobe of the aedeagus. The shape and chaetotaxy of tergite VIII often provide additional diagnostic characters. Nevertheless, a positive identification of females may not always be possible. The only regions where Anaulacaspis species can be identified with sufficient reliability based on external characters alone are Europe exclusive of the southeast and North Africa.

Diversity, zoogeography, and natural history: The overall distribution of Anaulacaspis is currently unknown (see introduction). The genus is currently represented in the Palaearctic region sensu SCHÜLKE & SMETANA (2015) by 31 species (disregarding a doubtful name), twelve of which are described for the first time. The generic assignment of one species is only tentative (see section on species groups above).

Except for the widespread A. nigra , Anaulacaspis species are confined to warmer climates in the south of the Palaearctic region ( Map 1 ). Some of them inhabit temporarily or permanently moist habitats in generally arid and semi-arid regions. Diversity hotspots in the Palaearctic region are the East Mediterranean (particularly Turkey), the Middle East (especially Iran), the Caucasus region, and Middle Asia. The countries with the greatest diversity are Iran (twelve species, three of them exclusive) and Turkey (six species, four exclusive), followed by Greece, Afghanistan, and Kyrgyzstan (four species each).

Some of the species are remarkably widespread. This particularly applies to Anaulacaspis nigra , whose confirmed distribution extends from West Europe to southern Turkey and Middle Asia. Several species, by contrast, are currently known only from their respective type localities.

Species of Anaulacaspis are generally found in moist habitats with sparse vegetation, mostly on the banks of temporary and permanent streams and rivers or on the shores of standing waters. At least one species, A. laevigata , may inhabit also swampy habitats. Anaulacaspis nigra has been found in a wide range of habitats such as different types of grassland, near running and standing waters, and even in nests of ants and mice.

Figures

Map 1: Distribution of Anaulacaspis in the Palaearctic region, based on revised records (all records pooled).

Figs 211–232: Anaulacaspsis formosa (211), A. elegans (212–220), A. beesoni (221–228; 224–225: lectotype), and A. inexpectata (229–232; 231–232: holotype): habitus (211; photo by Marc Tronquet); male tergite VIII (212, 221); male sternite VIII (213, 222); median lobe of aedeagus in lateral and in ventral view (214–217, 224–227, 229–232); female tergite VIII (218); posterior margin of female tergite VIII (219); female sternite VIII (220, 228); postero-lateral portion of sternite VIII (223). Scale bars: 211: 1.0 mm; 212–218, 220–222, 224–232: 0.1 mm; 219, 223: 0.05 mm.

Figs 1–12: Anaulacaspsis nigra. Maxilla (1); labium (2); labrum (3); male tergite VIII (4–9); male sternite VIII (10–12). Scale bars: 1–2, 4–12: 0.1 mm; 3: 0.05 mm.

Figs 164–186: Anaulacaspsis iberica (164–166), A. nigrina (167–172), A. beijingensis (173–177), A. taiwanica (178–183), and A. gilva (184–186): male tergite VIII (164, 167, 173, 178, 184); male sternite VIII (165, 168, 174, 179, 185); female sternite VIII (166, 172, 177, 183); median lobe of aedeagus in lateral and in ventral view (169–171, 175–176, 180–181); female tergite VIII (182); spermatheca (186). Scale bars: 0.1 mm.

Figs 187–210: Anaulacaspsis gilva (187–190), A. pectinata (191–195), and A. formosa (196–210; 199–200: Tunisia; 201–203: Morocco; 204–205: holotype of A. macra; 206: Murcia; 207–208: Andalucía): median lobe of aedeagus in lateral and in ventral view (187–188, 194–195, 199–208); female tergite VIII (189); female sternite VIII (190, 209); male tergite VIII (191, 196); posterior margin of male tergite VIII (192, 197); male sternite VIII (193, 198); spermatheca (210). Scale bars: 187–191, 193–196, 198–210: 0.1 mm; 192, 197: 0.05 mm.