Otostigmus ateles Chamberlin, 1920

(Figs 1–4)

Otostigmus n. sp. Kraepelin, 1916, Fig 2. Queensland, Australia. O. ateles Chamberlin, 1920, 14.

Diagnosis. Length 57 mm. antennal articles 17, the basal 2–2.5 glabrous. Forcipular coxosternal tooth-plates with 3+3 teeth. Tergites with complete paramedian sutures from 5, marginate from 6 or 8, posterior tergites with keels and spinules. Sternites with short anterior paramedian sutures and minute (?) tubercles on S15–18. Sternite of ultimate leg-bearing segment with shallow Y-shaped depression, sides diverging posteriorly and hind margin concave. Coxopleuron with two apical spines only. Legs 1–3 with two tarsal spurs.

Material examined. ZMUH. Syntype. Otostigmus n. sp. Queensl. Mjöberg. Malanda, juni. The specimen is contorted and difficult to examine.

Description. (Kraepelin’s (1916) data in parentheses where relevant). Length 57 mm. Antennal articles 17, the basal 2.66 glabrous (three basal articles almost glabrous) (Fig. 1). Each forcipular coxosternal tooth-plate with three main teeth, the lateral isolated, the inner two partially fused. With very small inner and outer subsidiary teeth (Fig. 2).

Tergites with paramedian sutures complete from 5 (begin on 5 or 6), marginate from 8 (6–8), (dorsal keel clear from 6–7, lateral longitudinal depressions from 7, posteriorly with longitudinal keels with fine spinules). Sternites with indication of median and median posterior depressions on some sternites and very small (?) tubercles on S17 and S18 (Fig. 3). Sternite of ultimate leg-bearing segment with shallow Y-shaped depression, sides diverging posteriorly and posterior margin concave (Fig. 4). Coxopleural process short with two apical spines, no lateral or dorsal spines.

Legs 1–2 with two tarsal spurs, leg 3 to at least 19 with one. Ultimate and penultimate legs missing.

Remarks. Kraepelin (1916) described two specimens without assigning them to a species as they lacked ultimate legs. Chamberlin (1920) listed the species as O. ateles without comment. It was not listed by Attems (1930).

This specimen shows close similarities to O. australianus but is much larger, 57 mm as compared to 32 mm in australianus, which Kraepelin described as young specimens. It also differs in the presence of keels with spinules on posterior tergites and sternites with short anterior paramedian sutures and minute tubercles. Further material allowing an investigation of individual and ontologenetic variation is required to clarify the relationship between O. ateles and O australianus (see under O. australianus below) but it would seem convenient to retain O. ateles pro tem.