Otostigmus (Parotostigmus) parvior Chamberlin, 1957 syn. nov.

Figs 41–46

Type material examined: Holotype (male), CAS 16670 (48-733), Ecuador, 14 mi. NE. Ambato, Tungurahua, 8.11.1955, E.I. Schilinger & E.S. Ross.

Redescription of holotype. Length: 40 mm from anterior margin of cephalic plate to posterior margin of tergite 21 (Figs 41, 42). Antennae with 17 articles (left) and 16 (right); first two basal and basal part of third glabrous. Cephalic plate smooth, without sutures and depressions, but with median sulcus [very short] in anterior part [almost slightly concave] (Fig. 43). Coxosternal tooth-plates wider than long, with 4+4 teeth, and a long bristle on each plate; coxosternite with a short paired sutures at base of tooth-plates, this suture is bifurcate in the sides and a short median longitudinal suture (Fig. 44). Trochanteroprefemoral process large, with the margin with one or two short tubercles and with the tip pointed. Tergites 6–20 with complete paramedian sutures; tergites 2–5 with very short incomplete paramedian sutures in the anterior and posterior margin; tergites 7–21 with a shallow median longitudinal keel; tergites 1–5 smooth; tergites 6-21 rugose, rugosity increasing from the anterior to posterior tergites; tergites 8-21 margined. Tergite 21 with posterior margin very slightly angulate, and with a shallow median longitudinal depression; tergite 21 with a shallow short median longitudinal keel (Fig. 45). Sternites 9–17 with incomplete paramedian sutures in anterior margin; sternites 4–19 with two small, rounded depressions arranged horizontally in the center; sternite 20 slightly concave. Sternite 21 with posterior margin straight, shorter than precedent, converging posteriorly (Fig. 46), with a shallow median longitudinal depression. Coxopleuron without spines. Pore-field covers almost entire coxopleuron, only the posterior end poreless. Posterior part of coxopleuron truncate, with a very short protuberance. Leg 1 with tibial spur; legs 1–5 with two tarsal spurs (in right legs 1–4); legs 6–19 with one tarsal spur, 20 and 21 without. Coxae 19 with a tiny protuberance; coxae 20 with a short appendix positioned posteriorly (Fig. 46). Prefemur of ultimate leg pair without spines, with a digitiform appendix somewhat exceeding half length of prefemur; digitiform appendix dorsoventrally flattened, with a tuft of hair at its dorsal tip.

Remarks. The holotype of O. parvior syn. nov. was poorly described, like O. mesethus . However, examination of O. parvior syn. nov. and comparison with O. mesethus suggests that the two species are very closely related. The main difference between the two species is the appendix of coxa 19, which is absent in O. parvior syn. nov. and very short in O. mesethus . Nevertheless, we consider O. parvior syn. nov. to be synonymous with O. mesethus . Next to the holotype, inside the vial, there is a label with the following statement “prob. not holotype rec. to CAS, viii.1994 ”. However, by examining the characters of the specimen available with the original description, it is possible to affirm that it is the holotype (male) described by Chamberlin (1957). Therefore, there is no doubt that the specimen redescribed above is the holotype designated by Chamberlin (1957).