Otostigmus (Otostigmus) Porat, 1876

Schileyko, Arkady A., Vahtera, Varpu & Edgecombe, Gregory D., 2020, An overview of the extant genera and subgenera of the order Scolopendromorpha (Chilopoda): a new identification key and updated diagnoses, Zootaxa 4825 (1), pp. 1-64 : 42

(!) 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).

Figures

FIGURES 78–83. Asanada sokotrana Pocock, 1899; BMNH 1934.2.15.151–154 78 LBS 21 ventrally; Asanada indica Jangi & Dass, 1984; Smaller ad. Rc 7484 79 head + LBS 1 dorsally; Asanada brevicornis Meinert, 1886; BMNH 1889.7.15.21–23 80 apical part of maxilla 2 dorso-laterally; Asanada sokotrana Pocock, 1899; BMNH 1899.7.4.85–86 81 LBS 20–21 and ultimate legs dorsally; Otostigmus (O.) multidens Haase, 1887; Ad. Rc 7510 82 right pleuron of LBS 3 laterally; Otostigmus (O.) multidens nordicus Schileyko, 1995; Ad. Rc 6747 83 left side of ultimate LBS + right ultimate leg medially; (an)—antenna, (cx)—coxopleuron, (f)—ultimate femur, (im)—intersclerite membrane, (p2)—pretarsus of maxilla 2, (pf)—ultimate prefemur, (pts)—non enlarged ultimate pretarsus, (s)—open spiracle with atrium, (su)—spines of ultimate prefemur, (T1)—tergite 1, (t1)—tarsus 1, (t2)—tarsus 2, (ti)—tibia, (ust)—ultimate sternite, (ut)—ultimate tergite.

FIGURES 89–96. Digitipes coonoorensis Jangi & Dass, 1984; Male CES 091088 89 femur of right ultimate leg medially; Digitipes sp.; Ad. Rc 7565 90 clypeal part of head ventrally 91 forcipular segment ventrally 92 LBS 13–15 ventrally; Otostigmus (O.) multidens nordicus Schileyko, 1995; Ad. Rc 6545 93 LBS 21 ventrally; Ad. Rc 6747 94 anterior part of head ventrally; Otostigmus (O.) astenus (Kohlrausch, 1881); MCZ DNA 102463 95 pretarsus of maxilla 2; Sad. Rc 7507 96 forcipular segment ventrally; (ap)—apical spines of coxopleural process, (as)—accessory spines, (bs)—basal suture of forcipular toothplate, (cl)—clypeus, (cx)—coxopleuron, (df)—conical distomedial process of ultimate femur, (f)—ultimate femur, (l)—labrum, (lc)—lateral spine of coxopleural process, (lsc)—sternal median longitudinal sulcus, (md)—medial longitudinal depression of ultimate femur, (p2)—pretarsus of maxilla 2, (pd)—sternal posterior depression, (pr)—trochantero-prefemoral process, (psl)—sternal paramedian sulci, (tp)—forcipular tooth-plate, (ust)—ultimate sternite.

FIGURES 84–88. Alipes multicostis Imhoff, 1854; Live specimen CDT (photo by Dmitry Telnov) 84 general view dorsally; Alipes grandidieri Lucas, 1864; BMNH 1959.3.8 85 distal part of ultimate leg laterally; Alipes appendiculatus Pocock, 1896; BMNH1950.3.9.2 86 forcipular segment ventrally 87 LBS 4–10 dorsally; Alipes grandidieri Lucas, 1864; BMNH1959.3.8 88 LBS 21 + prefemora of ultimate legs ventrally; (bs)—basal suture of forcipular tooth-plate, (cp)—very short spineless coxopleural process, (cx)—coxopleuron, (pf)—ultimate prefemur, (pr)—trochantero-prefemoral process, (t1)—flattened tarsus 1, (t2)—flattened tarsus 2, (T5)—terite 5, (ti)—flattened tibia, (tk)—tergal longitudinal keels, (tp)—forcipular tooth-plate, (ust)—ultimate sternite.