Guyanacaris Sakai, 2011

Kou, Qi, Poore, Gary C. B. & Liu, Xinming, 2024, Description of a new species of Guyanacaris Sakai, 2011 (Decapoda: Axiidea: Axiidae) from the South China Sea, Raffles Bulletin of Zoology 72, pp. 62-70 : 62-63

Genus Guyanacaris Sakai, 2011

Guyanacaris Sakai, 2011: 119–120 [type species: Calocaris (Calastacus) hirsutimana Boesch & Smalley, 1972 , by original designation, gender feminine]. – Dworschak & Poore, 2018: 62 (synonymy). – Poore, 2020: 264. – Padate et al., 2022: 196 (rediagnosis). – Poore & Ahyong, 2023: 199–200 (rediagnosis, synonymy).

Bruceaxius Sakai, 2011: 82–83 [type species: Acanthaxius polychaetes Sakai, 1994 , by original designation and monotypy, gender masculine]. – Padate et al., 2022: 202.

Neoaxius Sakai, 2017: 504–505 [type species: Neoaxius nicoyaensis Sakai, 2017 , by original designation and monotypy, gender masculine].

Remarks. For the most recent diagnoses of Guyanacaris Sakai, 2011 , see Padate et al. (2022) and Poore & Ahyong (2023). The genus is characterised by a mesial spine at the base of the scaphocerite, the presence of a male pleopod 1, curved lateral gastric carinae with several small spines, obsolete supraocular spines, a convex carapace profile and a depressed rostrum. Padate et al. (2022) agreed with Poore (2020) that Acanthaxius polychaetes Sakai, 1994 (type species of Bruceaxius Sakai, 2011 ) and A. spinosissima ( Rathbun, 1906) probably belong to Guyanacaris , thereby arguing that Bruceaxius Sakai, 2011 “should be considered to be a synonym of Guyanacaris ”. Poore & Ahyong (2023) synonymised the two genera. Padate et al. (2022) suggested that the second species, B. thailandensis Sakai, 2015 , lacks a mesial spine at the base of scaphocerite, differing from the typical Guyanacaris and “may be tentatively retained in Bruceaxius ”. However, B. thailandensis cannot be “retained” in Bruceaxius as its type species belongs in Guyanacaris . Furthermore, it is unclear in Sakai’s (2015: fig. 3A) illustration of B. thailandensis if the scaphocerite is shown at all — even if the mesial spine were absent, this would not be taxonomically significant at the genus level. As such, B. thailandensis is hereby transferred to Guyanacaris .

A key to the six species of Guyanacaris follows.