Mastigitae Fleming, 1815

Paweł Jałoszyński, 2018, World genera of Mastigitae: review of morphological structures and new ecological data (Coleoptera: Staphylinidae: Scydmaeninae), Zootaxa 4453 (1), pp. 1-119 : 9-12

Supertribe Mastigitae Fleming

Mastigitae Fleming, 1821; Grebennikov & Newton, 2009.

Mastiginae Fleming, 1821 ; Newton & Franz, 1998.

Mastigoidae Fleming, 1821: 49 (incorrect original spelling). Type genus: Mastigus Latreille, 1802 .

Mastigini sensu Reitter, 1882: 142. Type genus: Mastigus Latreille, 1802 .

Characteristics. Adults. Body ant-like, distinctly constricted between head and pronotum and between pronotum and elytra, elongate, convex or flattened, from yellowish to black, sometimes bicolored, with nearly black, dark brown or dark reddish-brown head and pronotum and testaceous, reddish or yellowish elytra; body length 1.10– 8.70 mm.

Head capsule elongate or transverse, prognathous; occipital constriction distinctly (often much) narrower than maximum width of head, dividing head capsule into exposed anterior part and narrow, subcylindrical 'neck' region largely retracted into prothorax; eyes typically located closer to mandibular bases than to occipital constriction, except for Papusus , in which eyes are submediam or subposterior; in some species eyes strongly reduced or absent; clypeus demarcated from frons by transverse groove or at least rapidly declined and at middle not confluent with frons.

Labrum transverse, with variously deep anteromedian emargination (except in some Clidicus ). Mandibles diverse, typically subtriangular, with mesal teeth (often more than one) and setose prostheca (except for Leptomastax , which has strongly modified and specialized mandibles). Maxillae with variously enlarged 4- segmented palps, which are highly diverse in shape, different in each tribe. Submentum not demarcated laterally by sutures; mentum subtrapezoidal; prementum prominent; labial palpomere II enlarged, typically broadest and longest, palpomere III much narrower than II, strongly elongate and pointed at apex.

Hypostomal ridges present, incomplete or nearly reaching posterior tentorial pits, the latter present and distinct, elongate or circular and always located in front of transverse impression demarcating ventrally 'neck' region. Gular plate lacking gular sutures, weakly transversely reticulated or nearly smooth.

Antennal insertions located anterodorsally, between or in front of eyes; scape enlarged, often strongly so, with deep apical emargination located typically lateroventrally or ventrally, so that antennae can bend between scape and pedicel; antennae very weakly and gradually thickened distally or not thickened.

Pronotum about as long as broad or (more frequently) elongate, broadest distinctly in front of middle or, rarely, at middle, with anterior corners rounded, posterior corners not marked or variously distinct and obtuse-angled, lateral edges or carinae absent; pronotal base lacking pits and grooves, or with an impressed transverse row of several pits, or with faint paired pits only. Basisternal part of prosternum as long as coxal part or longer, laterally fused with prothoracic hypomera, in some genera rudiments of notosternal sutures visible as short notches at anterior sternal margin or anterolateral margins of procoxal cavities; procoxal cavities broadly open or posteriorly delimited by overlapping (but not fused) postcoxal hypomeral lobes and lateral lobes of coxal portion of prosternum; prosternal process absent or developed as weakly elevated and diffuse carina, often broad anteriorly and narrowing posteriorly, in intact specimens hidden between contiguous procoxae. Hypomeral ridges absent.

Mesoscutellum in intact beetles entirely or nearly entirely covered by posterior pronotal margin, subtriangular, cordiform or subtrapezoidal; scutoscutellar suture absent.

Mesoventrite anteriorly forming a compact 'collar', which in intact beetles is inserted into posterior opening of prothorax (collar reduced in some Mastigini ), typically with median subtriangular expansion directed posterad (absent in some Mastigini and some Clidicini) and posteriorly demarcated by a transverse setose impression (reduced in some Mastigini ). Mesoventral intercoxal process distinctly but moderately broadly separating mesocoxae, variously developed but always flat or very weakly convex. Posterior margins of mesocoxal cavities typically carinate (indistinctly or not carinate in Mastigini ).

Metanotum largely reduced; structures associated with wing articulation absent, but alacristae, though somewhat shortened, are present even in entirely wingless genera.

Metaventrite broadening posteriorly, with metanepisterna largely exposed in ventral view in intact beetles, usually conspicuously broadened (except in Leptomastax and Mastigini ), metepimera strongly broadened; metacoxae broadly separated, posterior margin of metaventrite between metacoxae typically concave (straight in some Mastigini ).

Metendosternite (= furcasternum) with short, but sometimes very broad, laminar stem or virtually lacking stem and then lateral furcal arms are broadly separated and inserted each close to mesal margin of metacoxa.

Abdomen longer than metaventrite; six abdominal ventrites visible, ventrite I longer than any subsequent ventrite.

Elytra entire, suboval, lacking basal impressions, basal foveae and subhumeral carinae; humeri typically lacking humeral calli; elytral disc often with longitudinal rows of variously distinct punctures, sometimes very fine and barely discernible, rarely entirely absent.

Hind wings absent or (less frequently) present.

Legs with metacoxae about as long as broad, clearly divided into subglobose basal and subconical distal part.

Aedeagus elongate, median lobe symmetrical or asymmetrical; parameres present (in Mastigini one paramere may be reduced to various extent), lacking apical macrosetae; endophallus lacking sclerotized anchoring structures, except for dense tiny denticles on its inflatable membrane, flagellum short and straight or long and then forming several loops; diaphragm present and located on the opposite wall in relation to basal foramen; aedeagus, when asymmetrical, often twisted inside abdomen in such a way that terms 'dorsal' and 'ventral' are ambiguous and instead 'parameral' and 'abparameral' are used. Ductus ejaculatorius with 'sperm pump', which is a variously developed sclerotized elongate thickening of the ductus provided with external longitudinal muscle fibers that allow for changing its length, and consequently its inner volume, the pump often has one or both its ends provided with sclerotized funnel-like structures.

Spermatheca sclerotized, globular or strongly elongate, with a small accessory gland, ductus spermathecae moderately long, not coiled.

Characteristics. Larvae. Body campodeiform, subcylindrical or flattened, subparallel-sided to strongly narrowing posterad; legs long and slender. Pigmentation from creamy-white to orange, brown, up to nearly black, typically head, and tergal plates darker than remaining regions. Body moderately densely setose, setae unmodified or thickened, in some taxa additional tiny leaf-like setae present, in some taxa cuticle covered with dense asperities. Head prognathous, usually weakly tilted downward in living larvae, with or without an annuliform 'neck' and with one pair of stemmata; epicranial stem and frontal sutures distinct; nasale lacking teeth, with a pair of long teeth or with several small setiferous papillate protuberances. Antenna longer than head (from slightly to strikingly so) and very slender, not clubbed, long antennomeres I and II of similar diameter, antennomere III small and in some taxa vestigial, in some genera antennomere II subdivided into three parts, accessory appendage of antennomere II strongly elongate, spatulate or subconical. Mandibles falciform, moderately to very slender, pointed, each with one submedian mesal tooth or lacking teeth; maxillary mala undivided or stipital projection of maxilla with two lobes; maxillary palp long, with all palpomeres elongate. Thoracic tergites with distinct ecdysial lines at least on pronotum and mesonotum; sterna with paired (2–4) small setose sternal plates. Ten abdominal segments present, urogomphi absent or present and then each composed of one elongate segment fused with posterolateral margin of abdominal segment IX. Spiracles annular, ventrolateral or lateral, nine pairs: one on mesothorax and eight pairs on abdominal segments I–VIII.

Remarks. Although Mastigitae can be easily distinguished from all other Scydmaeninae on the basis of the general appearance of adults, diagnosis of this group is problematic because of high degree of morphological diversity. They share with Scydmaenini the basisternal part of prosternum fused laterally with prothoracic hypomera, and the broadly separated metacoxae, but various forms of the prosternal-hypomeral fusion can also be found in some Glandulariini , and the metacoxae are broadly separated in Cephenniitae. The great diversity of the forms of maxillary palps makes it difficult to use this structure to define a supertribe, but this character system can be used to distinguish Mastigitae from similar Scydmaenini . In the latter group the maxillary palpomere IV is always minute, dome-shaped and symmetrical, always narrower than the apex of palpomere III. In Mastigitae, the palps are typically strongly, usually conspicuously enlarged and the palpomere IV can be strongly asymmetrical, forming a compact oval together with the palpomere III, or flattened and subtriangular, or suboval and strongly elongate. The apical emargination of the enlarged scape in Mastigitae is typically located ventrally or ventrolaterally, whereas a similar emargination of not enlarged or indistinctly enlarged scape in Scydmaenini is typically dorsolateral (or absent). Mastigitae and Scydmaenini (one of the four currently recognized tribes of Scydmaenitae) were suggested to be sister groups ( Jałoszyński 2012a), and Scydmaenitae requires a profound reclassification as a paraphyletic group. An unexplored character system that may represent an autapomorphy of the tribes currently classified in Mastigitae is the tentorium with its dorsal arms fused with the vertex, so that at least in some taxa sites of fusion are marked on the surface as shallow impressions or dark spots visible through a lightly pigmented cuticle. This fusion may be unique for Mastigitae, but the tentorium remains poorly studied, especially in Scydmaenini and Glandulariini .

Composition and distribution. Mastigitae currently comprise six tribes with nine extant and six extinct genera; they include 128 extant species and subspecies, and fifteen extinct species. Two other extinct species, explicitly placed in or informally associated with Mastigitae, are here treated as Scydmaeninae incertae sedis or Coleoptera incertae sedis. The distribution of Mastigitae is strikingly disjunct and demonstrates the relict status of this group. Extant species of Mastigitae occur in the northern and north-eastern parts of the Mediterranean Basin, Southeast Asia and north-eastern Australia, South Africa, western United States, Central and northern part of Southern America. The largest numbers of genera and species are known from the Mediterranean Basin.