Otostigmus (Parotostigmus) silvestrii Kraepelin, 1903

Chagas-Jr, Amazonas & Souza, Emerson Marques, 2024, A review of the types of some Otostigmus (Parotostigmus) (Scolopendromorpha, Scolopendridae, Otostigminae) of the Andes mountain range, Zootaxa 5529 (3), pp. 436-460 : 454-455

Otostigmus (Parotostigmus) silvestrii Kraepelin, 1903

Type material examined: Syntypes ZMH, 1 male and 1 female, Ecuador, Pifo, F. 15.vii.1903, F. Silvestri .

Additional material examined: ZMUC, 1 specimen, Ecuador, Prov. Imbabura, 1 Km W. Otavalo, 2600 m, 17.vii.1990, Jonas Krat ; ZMUC, 1 specimen, Quito , 21.1.1920, H. Vorleck ; ZMUC, 6 specimens (3 males and 3 females), Quito, H. Vorleck, 9.ix.1912 ; ZMUC, 1 female, Quito, 15.1.1926, H. Vorleck ; ZMUC, Ecuador, 1 female, H. Vorleck ; ZMUC, 2 specimens (1 male and 1 female), Quito , 27.vi.1913, Bangast .

Redescription of syntypes. Length: 50 mm from anterior margin of cephalic plate to posterior margin of tergite 21. Antennae with 17 articles, first two and 1/3 of the dorsal face of third glabrous. Cephalic plate without sutures and depressions. Coxosternal tooth-plates with 4+4 teeth; coxosternite with a short paired sutures at base of tooth-plates [not described]. Tergites 6–20 with complete paramedian sutures [7 or 8 tergites]; tergites 9(10)– 21 margined [only tergite 21]; tergites 6–20 with [slight] median longitudinal keel [last three tergites]; tergite 21 with a slight short median longitudinal keel and a shallow rounded depression in posterior margin. Sternites smooth, without sutures, but with depressions; a larger rounded depression in the center and three small, rounded depressions arranged at posterior margin as an inverted triangle [with 3 anterior longitudinal pits and 3 rounded pits in front of the rear margin]. Sternite 21 shorter than precedent, with a shallow median longitudinal depression [not described]; sternite 21 with posterior margin slightly concave [posterior margin truncated and rounded or indented]. Coxopleuron without spines, short and truncate. Pore-field covers almost entire coxopleuron, only the posterior end poreless. Legs 1–19 with one tarsal spur, 20 and 21 without. Coxae 19 in males and females with a shorter appendix [not described]; coxae 20 in male with a curved appendix posteriorly, but that not overlying sternite 21; coxae 20 in female with a shorter appendix. Prefemur of ultimate legs in male with a digitiform appendix ¾ length of prefemur; digitiform appendix slightly flattened dorsally and with a tuft of blond hairs in its dorsal tips; females without digitiform appendix.

Remarks. In males, there is a claviform [digitiform] appendix on the prefemur of the ultimate legs. This appendix is absent in females. In addition, there is a larger appendix on the coxa of the 20th leg in males. In females this appendix is very short. In addition, males have a short appendix on the coxa of leg 19. Otostigmus silvestrii bears a strong resemblance to O. insignis , O. lavanus and O. silvestrii intermedius , including tergites, sternites and leg characters, as well as external sexual characters. However, it differs mainly in the shape and size [length] of the appendix on coxae 20. In O. silvestrii , the appendix is shorter and does not extend beyond sternite 21, and it lacks a hook shape. Conversely, in O. insignis , O. lavanus , and O. silvestrii intermedius , the appendix on coxae 20 is larger, exceeds sternite 21, and has a hook shape. The differences in shape and size of the digitiform appendage in O. silvestrii compared to other taxa mentioned above may be ontogenetic, but the type specimen appears to resemble an adult. Therefore, O. silvestrii is maintained as a valid species.