Bang et al. [1] described the two new Longipedia species from Korea, and suggested that the L. gonzalezi Schizas et al., 2015 from Puerto Rico in the northeast Caribbean Sea should be treated as a junior subjective synonym of L. americana Wells, 1980.
Schizas et al. [2] suggested in their publication the two morphological features of L. gonzalezi that can be distinguished from L. americana: (1) sharp protrusions of the P2 basis, and (2) P3 and P4 coxa without spinules. However, according to the original description of L. americana by Wells (Figure 220; p. 165, [3]), and the other publication by Onbé (Figure 81; p. 626, [4]), the sharp protrusion is observed on the P2 basis, between the endopod and exopod. Therefore, since it is difficult to distinguish between the two species only with one difference (the presence or absence of spinules of P3 and P4 coxa), Bang et al. [1] proposed to treat that L. gonzalezi as a junior subjective synonym of L. americana.
Later, Schizas et al. [5] have argued in ‘Comment’ that sharp projection on the P2 basis of L. americana is absent in the original publication of L. americana, but this is not, and they stated P2 coxa, which seems to be a typo in P2 basis. In all species of Longipedia, no sharp process is observed in P2 coxa. Furthermore, Schizas et al. [5] mentioned the DNA divergence between L. americana and L. gonzalezi, but did not provide molecular data for this.
Furthermore, Schizas et al. [5] described three additional differences between the two species in ‘comment’ as follows: (1) The male of L. gonzalezi with three lateral spinules in the telson, only two in L. americana; (2) Both sexes of L. gonzalezi with smooth body, L. americana with dorsal and ventral urosomal spinules; and (3) P6 fused to the urosome in L. gonzalezi; both P6 swimming legs separated in L. americana.
- (1)
- Anal operculum (not anal somite) with a strong median spine and three lateral spines (Not spinules) on each side in male L. gonzalezi, only two lateral spines in L. americana;
- (2)
- There is no difference between the two species in the surface ornamentation; surface ornamentation is extremely sparse in L. americana as in L. gonzalezi. This is specified in the original description of Schizas et al. (Table 3; p. 10 in [2]).
- (3)
- Most Longipedia species exhibit asymmetric P6 in males. However, male L. gonzalezi is not only asymmetric but also fused to genital somite. This character can be an important feature of identifying species because it was first reported in Longipedia.
We strongly agree with Wells [3] and Schizas et al. [5] that Longipedia specimens are notoriously difficult to allocate to species and in most cases, species differentiation is based on slight differences. Therefore, considering several additional points mentioned in the ‘comments’ of Schizas et al., Bang et al. could withdraw their suggestion to treat L. gonzalezi as a junior subjective synonym of L. americana.
Funding
This research received no external funding.
Conflicts of Interest
The authors declare no conflict of interest.
References
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