Neocaridina aff. fukiensis (Liang & Yan, 1978)

Shih, Hsi-Te, Cai, Yixiong, Niwa, Nobuaki, Yoshigou, Hidenori & Nakahara, Yasuhiko, 2024, Fig. 4. A in Positive association between PTN polymorphisms and schizophrenia in Northeast Chinese Han population., Zoological Studies 63 (18), pp. 141-149 : 22

Neocaridina aff. fukiensis ( Fig. 11 )

Specimens examined: Japan: 1 male, cl 6.6 mm, 1 male, cl 5.7 mm, 1 male, cl 6.0 mm, 10 males, cl 3.7–5.8 mm, NCHUZOOL 14946, 1 female, cl 7.7 mm, 1 female, cl 4.5 mm, NCHUZOOL 14947, Kaya R., Ashida River system, Fukuyama City, Hiroshima Prefecture, N34°36'43", E133°15'33'', coll. H. Yoshigou, 17 Oct. 2015; 1 male, cl 4.5 mm, 1 male, cl 4.2 mm, 14 males, cl 3.8–5.7 mm, ZRC 2023.0219, Kaya R., Ashida River system, Fukuyama City, Hiroshima Prefecture, N34°36'43", E133°15'33'', coll. H. Yoshigou, 1 Dec. 2016.

Remarks: This species morphologically resembles Neocaridina fukiensis (Liang & Yan, 1978) including the form of its rostrum, which is elongated, reaching beyond the end of the antennular peduncle and with a slight upward curve distally; the telson terminates in a prominent projection; no sexual dimorphism in the third pereiopods; and the form of the appendix interna and the appendix masculina of the male second pleopods, with the appendix interna projecting out distinctly from the appendix masculina ( Fig. 11 ). However, the endopod of the male first pleopods does not possess a distinct projection at its base (vs. with a distinct projection in N. fukiensis ) and the fewer spines on the flexor margin of dactylus of the third pereiopods (6–7 vs. 9–10 in N. fukiensis ) can be used to separate the two species easily.

Fuke et al. (2021) assigned specimens collected from Miya River, Yufuin, Oita to “ Neocaridina sp. ” based on both morphological and molecular analyses. Upon re-analysis of their COI sequence data (LC612372, LC612374, LC612376, LC612378, LC612379) in conjunction with our own data, the findings revealed that the Miya material clusters in a clade with our Fukuyama specimens, suggesting they are conspecific ( Fig. 3 ). Despite these findings, a pending detailed morphological examination is necessary to confirm the identity of this clade, as it may represent an undescribed native species endemic to Japan. Additional geographic data are requisite to accurately establish its distributional range.

Figures

Fig. 11. Neocaridina aff. fukiensis. (A) cephalothorax and cephalic appendages, lateral view; (B, C) 1st pereiopod; (D) 2nd pereiopod; (E) same, basis; (F) male 1st pleopod; (G, H) male 2nd pleopod. Scale bars: A–D = 0.5 mm; E–H = 0.2 mm (male, cl 5.7 mm, NCHUZOOL 14946, Kaya R., Ashida River system, Fukuyama City, Hiroshima Prefecture, N34°36'43", E133°15'33'', coll. H. Yoshigou, 17 Oct. 2015).

Fig. 3. Bayesian inference (BI) tree for species of the genus Neocaridina from the East Asia Arc and the related taxa from East Asia, based on the cytochrome c oxidase subunit I (COI) gene. Probability values at the nodes represent support values for BI and maximum likelihood (ML). Only support values> 50% are shown on the nodes. For haplotype names, see table 1. *, sequences downloaded from GenBank.