Sterropristini

Diagnosis. Antenna short or very short (i. e. reaching at most the anterior margin of tergite 3 when reflexed) and tapering (Fig. 122), its basal articles visibly wider than long, flattened and much broadened. Median tooth of labrum small. Forcipular tooth-plates (Figs 120, 121) well developed, their basal sutures form a very characteristic “ W ”. Trochantero-prefemoral process virtually absent (in Sterropristes violaceus Muadsub and Panha 2012, fig. 10 B of Muadsub et al. 2012) or rudimentary, rounded apically (in S. sarasinorum Attems, 1934 and S. metallicus (Verhoeff, 1937), figs 3 A and 5 B of Muadsub et al. 2012, respectively). Tarsungula unusually (for Otostigminae) short and broade, nearly triangular and very slightly curved (Figs 120, 121); their inner / ventral surface is saw-like, bearing 8 – 13 blunt serrations. Tergites lacking longitudinal keels. Sternites with well-developed paramedian sutures (in most specimens complete in the LBS of posterior half of body). LBS 7 with spiracles, the latter with deep, well-developed atrium. Pleuron with intersclerite membrane well visible, without set of longitudinal pleurites anteriorly. Legs with tarsal spur (s). Coxopleuron of varied length but lacking process (Figs 119 and 123, figs 4 F, 4 F, 5 D of Muadsub et al. 2012). Ultimate leg truly “ pincer-shaped ” (Fig. 119), its prefemur without either spines or corner spine; pretarsus visibly longer than tarsus 2 and lacks accessory spurs; tarsal articles and / or tibia with prominent bulge ventrally. Number of subtaxa. 1 genus (“ Two species in two genera ” sensu Edgecombe & Bonato 2011: 403). Sexual dimorphism. Unknown. Range. Tomohon, Sulawesi (Indonesia); Penang (Malaysia); Similan and Surin Islands in Andaman Sea (Phangnga Province, South-Western Thailand).

Remarks. Treated as a tribe in Edgecombe & Bonato (2011: 403), Muadsub et al. (2012: 36) and Vahtera et al. (2013: 581, 594). But Vahtera et al. (2013: 594) wrote later: “ However, a recurring pattern is that most trees depict Sterropristes / Sterropristini nested within Otostigmini (…), in which case recognition of Sterropristini as a tribe … renders Otostigmini paraphyletic ”. Nesting of Sterropristes within Otostigmini has been recovered in more recent molecular phylogenies as well (Siriwut et al. 2018; Joshi et al. 2020). We presently retain Sterropristini as a tribe here as the last reviewers (Vahtera et al. 2013) did not formally eliminate this tribe. The structure of the labrum of Sterropristini is not detailed in the ventral view of the head of Sterropristes metallicus (fig. 5 A in Muadsub et al. 2012).