Otostigmus consonensis, Vu & Eguchi & Le & Nguyen & Nguyen, 2022

Vu, Ha T., Eguchi, Katsuyuki, Le, Son X., Nguyen, Thu-Anh T. & Nguyen, Anh D., 2022, A new species and a new record of the genus Otostigmus Porat, 1876 (Chilopoda Scolopendromorpha: Scolopendridae) in Vietnam, Zootaxa 5129 (1), pp. 60-76 : 64-67

publication ID	https://doi.org/ 10.11646/zootaxa.5129.1.3
publication LSID	lsid:zoobank.org:pub:2BC9288D-0F6A-446D-A6D2-C1FF37DBB4E5
DOI	https://doi.org/10.5281/zenodo.6487812
persistent identifier	https://treatment.plazi.org/id/284DFD62-570C-FFC1-AB84-22FF9FF4F825
treatment provided by	Plazi
scientific name	Otostigmus consonensis
status	sp. nov.

Treatment

Otostigmus consonensis sp. nov.

( Figs. 1 View FIGURE 1 , 2–4 View FIGURE 2 View FIGURE 3 View FIGURE 4 )

Material examined

Holotype. Ba Ria - Vung Tau Province, Con Dao National Park , Hon Ba trail; 08.65026N, 106.55683E; 35 m a.s.l.; 09 Nov. 2019; Vu Thi Ha leg.; natural forest; IEBR-Chi326. GoogleMaps

Paratypes. Six specimens; the same data as for holotype; IEBR-Chi325, IEBR-Chi331, IEBR-Chi332, IEBR- Chi333, IEBR-Chi377, IEBR-Chi379.

Diagnosis

Otostigmus consonensis sp. nov. differs from its congeners by 18 antennomeres (of them, 2.3–2.5 basal ones are glabrous); forcipular tooth plates with 3 + 3 teeth; tergites 5–20 with complete paramedian sutures; sternites with incomplete paramedian sutures; the ultimate leg with 11–15 prefemoral spines.

Description

Color: Antennae, head and tergites blackish blue, whereas other parts yellow. Body length, ca. 30 mm; width, LBS 10 сa. 1.2 mm.

Head: Cephalic plate with an incomplete median longitudinal sulcus, puncta and setae, and lateral marginations ( Fig. 1A View FIGURE 1 ). Antennae with 18 antennomeres, 2.3–2.5 glabrous basal ones ( Fig. 2A–B View FIGURE 2 ).

Forcipular segment: coxosternite not setose; tooth plates well-developed, completely separated; each plate with three teeth: a larger and two smaller. Trochanteroprefemur processes with two tiny or only traces of teeth ( Fig. 2D View FIGURE 2 ).

Tergites 1–4 without sutures or keels; tergites 5–20 with complete paramedian sutures ( Fig. 3A View FIGURE 3 presents the paramedian structure on tergites 9–10). The last tergite without sulcus ( Fig. 3C View FIGURE 3 ). Spiracles oval, on LBS 3, 5, 8, 10, 12, 14, 16, 18, 20 ( Fig. 4A View FIGURE 4 presents the spiracle on segment 10).

Sternites not setose; paramedian sutures incomplete; marginations absent ( Fig. 3B View FIGURE 3 ). Ultimate sternite subtrapeziform with concave posterior margin ( Fig. 3D View FIGURE 3 ).

Ultimate LBS: coxopleuron with many large pores covering nearly all its surface ( Fig. 3D View FIGURE 3 ); coxopleural process short, with 2 apical, 1 subapical, and 1 lateral spines ( Fig. 3D View FIGURE 3 ).

Legs long and slender. Leg 1 with 2 tarsal spurs ( Fig. 4B View FIGURE 4 ), 1 tibial and 1 femoral spur; legs 2–20 with only 1 tarsal spur, without tibial and femoral spurs.

The ultimate leg very long and slender, with 14 relatively thin prefemoral spines: 1 located on the corner, 2 dorsomedial, 7 medial and 4 ventromedial ones ( Fig. 4 View FIGURE 4 C-D).

Variability

The number of prefemoral spines varies from 11 to 15, including 1–2 dorsomedial spines, 4–7 medial spines, and 2–5 ventromedial spines. The number of coxopleural spines also varies from 2 (1 apical, 1 subapical) to 4 (2 apical, 1 subapical, and 1 lateral).

Etymology

Named after the “Con Son” Island, the largest island of Con Dao National Park, where type series were collected.

Distribution

The new species was found only in the Con Son Island, which is about 80 km from the mainland of southern Vietnam.

Remarks

The number of glabrous basal antennomeres is systematically important ( Schileyko 1995). By having 2–2.5 ones, the new species is close to O. astenus , O. multidens , O. scaber , and O. spinosus . The new species is different from O. scaber in the absence of longitudinal tergal keels and sternites lacking (or poorly developed) paramedian sutures. Otostigmus consonensis readily differs from all the aforementioned species (except for O. astenus ) in having 3 + 3 (vs. 4 + 4 or even more) teeth of forcipular tooth plates. Two other diagnostic characters are the number of antennomeres (18 vs. 17 or 19–24) and the number of coxopleural spines (3–4 vs. more than 4), but both of them may be a subject in individual variability in Otostigmus s. str. and should not be used alone for distinguishing species in this taxon (as suggested by Schileyko et al., 2020)

The new species is closely related to O. voprosus . Both have 18 antennomeres, a tooth plate with three distinct teeth, and tergites with paramedian sutures, but they can be distinguished by the number of glabrous basal antennomeres (2.3–2.5 in the new species vs. 2.5–3 in O. voprosus ), the number of coxopleural spines (3–4 vs. 5), and the number of tarsal spurs on legs 2 and 3 (2 vs. 1). The phylogenetic analysis also revealed that O. voprosus is a sister species of the new one ( Fig. 9 View FIGURE 9 ).

A detailed comparison between the new species and Otostigmus species recorded in Vietnam is presented in Table 2 View TABLE 2 .