(!) Otostigmus (Otostigmus) Porat, 1876

Figs 82, 83, 93–96

Type species. Otostigmus carinatus Porat, 1876 (by subsequent designation of Pocock 1891).

It should be noted that O. carinatus has been synonymised to O. scaber (described by Porat in the same paper of 1876) by Kraepelin (1903: 111). Also, Bonato et al. (2016) correctly mentioned that the type species of Otostigmus sensu stricto was fixed by Pocock (1891: 229), but they erroneously wrote that the type species of Otostigmus was fixed by Attems[!] (1930: 229), whereas in fact Attems erroneously mentioned as a type species O. orientalis Porat, 1876 (p. 129 therein).

Diagnosis. Median tooth of labrum well developed (Fig. 94). Second article of telopodite of maxilla 2 with (in most species) or without dorsal distal spur; pretarsus with 1 or 2 (Fig. 95) accessory spines. Forcipular tooth-plates present, trochantero-prefemur with well-developed process (Fig. 96). In a few species tergites with longitudinal keels (fig. 16 in Schileyko & Stoev 2016). Sternites with paramedian sutures (more rarely sulci) developed to varying degrees and, sometimes with median and paired lateral depressions. LBS 7 lacking spiracles, the latter in most species with deep atrium (Fig. 82). Legs with tarsal spur(s) in the overwhelming majority of species. Posterior margin of male ultimate tergite without elongated projection. Coxopleural process in most species well-developed (if so, it is oriented caudad; Fig. 93), with apical (in most species plus lateral and sometimes plus dorsal) spines; in a few species coxopleural process much reduced (figs 59, 60 in Lewis 2014). Prefemur of the ultimate leg with spines (Fig. 83) and with or without (more or less developed) corner spine, pretarsus well-developed.

Number of species. 58 (Lewis 2014: 388).

Sexual dimorphism. Unknown.

Remarks. Treated as a subgenus in Lewis (2010b: 1, 2014: 388), Edgecombe & Bonato (2011: 400), Schileyko & Stoev (2016: 253); the latter is the most recent morphological account on Otostigmus (Otostigmus) .

In the nominotypical subgenus the presence and number of the maxilla 2 spurs and accessory spines may be subject to both individual and interspecific variability, thus these characters cannot be used (alone) in Otostigmus for separating species as well as subgenera.

Traditionally the presence of both tergal keels (Fig. 87) and spinules are used in Otostigminae as one of the main diagnostic characters. However, it has been already mentioned (Schileyko & Stoev (2016: 255) that presence of the tergal keels is not always reliable for distinguishing species in Otostigmus (Otostigmus) because it may be species-specific (eg, O. scaber Porat, 1876, O. amballae Chamberlin, 1913, O. orientalis Porat, 1876), whereas it varies significantly in other species (eg, O. multidens Haase, 1887). The presence of tergal spinules may also vary intraspecifically in Otostigmus (Otostigmus) from well-developed to nearly absent, so both these characters should not be used alone in the corresponding keys.

According to recent molecular investigations that include most genera of Otostigminae the genus Otostigmus (in general) is non-monophyletic (Siriwut et al. 2018). Vahtera et al. (2014: 7) wrote that “ Otostigmus is likewise polyphyletic in all three analyses but can be seen to comprise three groupings that have biogeographic signal: a basal grade is composed of Asian and Pacific species, whereas the exemplars from North Africa and the Canary Islands … and the Caribbean … are allied to other otostigmine genera” (see also below).