Australian Biological Resources Study

Australian Faunal Directory

Subfamily Pselaphinae Latreille, 1802

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Subfamily Pselaphinae Latreille, 1802

 

Introduction

Pselaphinae, commonly known as ant-like litter beetles, are a diverse group of small beetles typically associated with leaf litter and rotten wood. The average body length is about 1.5 mm, with extremes ranging from 0.4 to 7.1 mm. They are a perfect example of the enormous group of small beetles (Park 1964). Worldwide, some 9,000 species in over 1,200 extant genera are known. This section of the Australian Faunal Directory records 579 species in 163 genera from Australia but estimates indicate a fauna of at least 1,600 species. Some species exhibit promise as indicators of old-growth forests.

Pselaphines are predators as larvae and adults, feeding on small invertebrates such as mites, Collembola, worms and Symphyla. Immatures are poorly known and only a few species have their larval stage described. De Marzo (1986) found that larvae of one species secreted small viscous droplets from the abdominal glands onto the long dorsal setae. The abdomen is curved over the head when Collembola are approached and the setae quickly brushed against them. They stick to these setae and the larvae can then leisurely feed upon their prey. De Marzo (1988) also found that the larva of another species uses sticky, protrusible organs at the front of the head to capture Collembola.

Adults are typically associated with leaf litter and woody debris of forests, and while their greatest species richness is reached in forest habitats, members can be found in all types of wetland, grassland, desert, beach, cave and arboreal habitats (Park 1964; Newton & Chandler 1989; Chandler 1990; Chandler 2001). As long as organic debris, moss, root mats, or seepage through rocks maintain a zone of high humidity where prey exist, pselaphines may be found.

Members of one supertribe, the Clavigeratae, are all believed to be obligate myrmecophiles, and may be found only in the colonies or moving in columns of their hosts outside the nests. These species feed on living or dead larvae of the host ants, and may also be fed by trophallaxis.

 

Diagnosis

The pselaphines are readily recognized due to their distinctive appearance. They are typically more compact than most other staphylinids, small (0.5-5.5 mm in length, average length 1.5 mm), the head and pronotum are usually narrower than the elytra, the antennae are apically clubbed in all but the Faronitae and a few myrmecophilous groups, and they possess a unique pattern of foveae that becomes reduced in the more derived groups. They also have: antennae inserted under shelf-like frontal projections; usually 11 antennomeres, but with 10, 9, 6, 5, or 3 antennomeres in a few genera (also with 4-8 antennomeres in a few genera from other regions); maxillary palpi with 1-4 (usually 4) palpal segments and a small setiform or cone-like apical pseudosegment (appearing to be a fifth segment in many physically large genera); procoxal fissure closed, trochantin concealed; tarsi 3-3-3 (2-2-2 in Bythinoplectini, Dimerini, and Mayetiini); abdomen with paratergites associated with the first three or (usually) four visible tergites, paratergites are sometimes mostly or entirely fused to their associated tergite and /or sternite (Clavigeritae with tergites of first three visible segments (IV-VI) fused to each other); males with venter of seventh visible segment composed of three sclerites (two in a few groups), median sclerite the penial plate (sternite IX), the lateral sclerites are derived from tergite IX.

 

ID Keys

Keys to Australian supertribes. For full details, see (Chandler, D.S., 2001) [41].

1. Elytra usually with discal foveae (def, Fig. 1) in addition to basal foveae; prothorax with median procoxal fovea (mpcf, Fig. 1); first two tarsomeres short, subequal, with two equal tarsal claws (Fig. 18); body elongate and flattened; antennae clavate, lacking distinct antennal club … Faronitae

Elytral only with basal foveae, or foveae lacking; lacking median procoxal fovea; tarsomere lengths and body form variable; antennae typically with distinct club formed by apical one to three segments, or club not formed in two genera with six or fewer antennal segments … 2

2. (1) Mesofemora distant from mesocoxae, dorsal margin of mesotrochanters longer than trochanter width (Fig. 17) … 3

Mesofemora close to mesocoxae, dorsal margin of mesotrochanters very short (Fig. 12) … 4

3. (2) With six or fewer antennomeres, apical antennomeres not widened to form a distinct club; abdomen with tuft of thick setae on basal half of first paratergite, first three visible tergites (IV-VI) fused, often forming a continuous plate (Fig. 192: see Clavigeropsis australiae); basal two tarsomeres very short, with single claw (Fig. 19) … Clavigeritae

With eleven antennomeres, apical 1-3 antennomeres usually widened to form club; abdomen lacking tuft of setae at basolateral margins, first three visible tergites (IV-VI) free; second tarsomeres clearly longer than first in all but two genera Fig. 20) … Pselaphitae

4. (2) Antennal scape distinctly notched at dorsal apex (Fig. 10); pronotum usually with 1-2 pairs of basolateral foveae (iblf and oblf, Fig. 1); abdomen often lacking sharply defined margins lateral to visible tergites 2-4 (V-VII); mesopleural suture extending from lateral margin of mesocoxae to elytra, suture often forming an elongate setose sulcus … Batrisitae

Antennal scape usually with dorsal apical margin straight (Fig. 9); pronotum usually lacking basolateral foveae; abdomen usually with angular margins lateral to visible tergites 2-4 (V-VII), but certain genera of Goniaceritae (Proterini [Pareuplectops, Fig. 141: see Pareuplectops styx], Iniocyphini [Sunorfa, Fig. 137: see Sunorfa nigripes], and Brachyglutini [Batraxis, Fig. 113: see Batraxis armitagei] with rounded lateral margins; mesopleural sulcus variable, never deep and setose … 5

5. (4) Metacoxae contiguous (separated in some non-Australian genera), strongly projecting at point of articulation with metatrochanters (Fig. 1); pronotum with antebasal sulcus usually present (as, Fig. 1); body usually depressed and linear … Euplectitae

Metacoxae moderately to widely separated (contiguous in some non-Australian groups), relatively flat and only slightly projecting at point of articulation with metatrochanters (Fig. 12); pronotum with antebasal sulcus usually lacking (present in Rybaxis and closely related genera); body usually convex and often more globular … Goniaceritae





Dorsal features (left side). HEAD: ff, frontal fovea; vf, vertexal fovea; iab, interantennal bridge; at, antennal tubercle; dpp, dorsal postantennal pit; vs, vertexal sulcus. PROTHORAX: aldf, anterolateral discal fovea; ldf, lateral discal fovea; maf, median antebasal fovea; laf, lateral antebasal fovea; oblf, iblf, outer and inner basolateral fovea; lls, lateral longitudinal sulcus; mls, median longitudinal sulcus; as, antebasal sulcus. ELYTRA: sef, subbasal elytral fovea; bef, basal elytral fovea; shef, subhumeral elytral fovea; def, discal elytral fovea; ds, discal stria; ss, sutural stria. ABDOMEN: ptf, paratergal fovea; blf, basolateral fovea; mbf, mediobasal fovea; dc, discal carina.

Ventral features (right side). HEAD: gf, gular fovea; gc, gular carina; agt, apicolateral gular tubercles. PROTHORAX: apsf, anteroprosternal fovea; lpcf, lateral procoxal fovea; mpcf, median procoxal fovea; pef, proepimeral fovea; mpc, median prosternal carina. MESO- and METATHORAX: ppf, prepectal fovea; lmsf, lateral mesosternal fovea; almsf, anterolateral mesosternal fovea; mmsf, median mesosternal fovea; mmtf, medain metasternal fovea. ABDOMEN: blf, basolateral fovea; mbf, mediobasal fovea.










 

History of changes

Note that this list may be incomplete for dates prior to September 2013.
Published As part of group Action Date Action Type Compiler(s)
01-Jul-2020 21-Dec-2011 MODIFIED
12-Feb-2010 (import)