Rhyacobates gongvo Tran & Yang, 2006

Figs 3K, 4H, 5J, 7A

Rhyacobates gongvo Tran & Yang, 2006: 16–19, figs 17–25, 28 (original description).

Rhyacobates gongvo – Tran & Nguyen 2016: 513, figs 41–42 (with remarks).

Diagnosis

Body length of apterous females 7.80–8.30, of apterous males 6.20–6.50. Color (Figs 3K, 4H): head yellow with black markings; pronotum: of female with a large subtriangular yellow marking, of male with subovate yellow spot; in apterous form, mesonotum with yellow median stripe; metanotum: of female completely black, without yellow markings, of male chiefly black, usually with very thin yellow median stripe. Female: abdomen elongate and straight (Fig. 5J); ventral length of pregenital abdomen about 0.4 times body length; posterior part of abdominal segment VII slightly depressed dorso-ventrally; connexival processes of segment VII long, straight, flat (Fig. 3K); sternum VII not totally enclosing genital segments, posterior margin straight, without process (Fig. 3K). Male: length of middle tibia ca 2.1 times length of hind tibia; pygophore simple; proctiger with angular lobes laterally (Fig. 7A); paramere slender, strongly curved at basal third, then tapering towards narrow apex.

Material examined

Type specimens

See Tran & Yang (2006).

Non-type specimens

VIETNAM • 1 ♁, 1 ♀ (apterous); Lào Cai Province, Sa Pa, Cát Cát, Ho stream (feeder stream of Mường Hoa stream); 22°19′32.9″ N, 103°49′52.9″ E; 27 Oct. 2020; A.D. Tran leg.; TAD20-23; ZVNU • 1 ♀ (apterous); same collection data as for preceding; NKUM .

GPS data of previous records: see Tran & Yang (2006), Tran & Nguyen (2016).

Distribution

Vietnam: Lào Cai (Tran & Yang 2006; Tran & Nguyen 2016).

Comparative notes

This species is most similar to R. malaisei, which was discussed by Tran & Yang (2006: 18–19). Here, we provide further comparative notes between the two species. Rhyacobates gongvo and R. malaisei share the following characteristics of the female: (1) the metanotum is completely black, without yellow markings (Fig. 3K, M); (2) the abdomen is relatively straight and elongate; (3) the connexiva of abdominal segments I–VI are blackish, forming straight lines in dorsal view (Fig. 3K, M); (4) abdominal segment VII has a pair of pointed or angular lateral processes (Figs 3K, 5J, L, 30G); and (5) the posterior margin of sternum VII is truncate or slightly sunken, without a median process (Fig. 30F). The key differences between these two species are as follows: in the female of R. gongvo, the connexiva of abdominal segment VII do not meet each other over the dorsum (Fig. 3K), whereas in the female of R. malaisei, the connexiva of abdominal segment VII are more developed, curved mesad and meeting over the middle of the abdominal dorsum (Figs 3M, 30D–E). In the male of R. gongvo, the lateral lobes of the proctiger are angular (Fig. 7A), whereas in R. malaisei, each lateral lobe of the proctiger has an angular process directed ventrad (Figs 7C, 30K).