Boccardia pseudonatrix Day, 1961

Abe, Hirokazu & Sato-Okoshi, Waka, 2021, Molecular identification and larval morphology of spionid polychaetes (Annelida, Spionidae) from northeastern Japan, ZooKeys 1015, pp. 1-86 : 1

Boccardia pseudonatrix Day, 1961 Fig. 7C

Larval morphology.

Slender and fusiform in overall body shape. Prostomium rounded with a slight anterior notch. Three pairs of eyes present, most median pair rounded and lateral pairs double-eyes. Body entirely faint yellow. Dorsal melanophore absent, slight black pigmentation present (Fig. 7C , left). Pygidium with dorsal gap, pigmented with yellow. Internally, the vestibule and pharynx brown or black, gut green in color. Gastrotrochs on chaetigers V and VII.

Remarks.

Adults of this species were non-boring and collected from mud deposits in crevices of shells of living C. gigas oysters in Tomiura. Adult morphology (see Abe et al. 2019b) agrees with the descriptions of B. pseudonatrix from South Africa ( Day 1967; Simon et al. 2010) and Australia ( Sato-Okoshi et al. 2008, as B. knoxi ; see Walker 2013). The 18S rRNA gene sequences obtained in the present study completely match (1714/1714 bp) that of B. pseudonatrix from South Africa (KY677895) reported by Williams et al. (2017) (Fig. 3 ). Therefore, this species was referred to B. pseudonatrix .

Boccardia pseudonatrix has been reported to have adelphophagic larvae with a short or absent planktonic phase ( Sato-Okoshi et al. 2008; Simon 2015). The larvae herein reported accidentally hatched from egg capsules in an adult tube during the process of extraction of the adult specimens.

Figures

Figure 3. Maximum Likelihood tree inferred from nuclear 18 S and mitochondrial 16 S rRNA gene sequences of spionid polychaetes obtained from Japan in the present and previous studies (shown in Table 1) and from DDBJ / EMBL / GenBank (shown in Table 2). The tree is divided into two parts A, B. The gene sequences obtained in the present study are highlighted by bold and red color and the adult and larval sequences are indicated by solid squares and circles in front of each species name, respectively. SH-aLRT / approximate Bayes support / ultrafast bootstrap support values of ≥ 80 % / ≥ 0.95 / ≥ 95 %, respectively are given beside the respective nodes. Nodes with red circles indicate triple high support values of SH-aLRT ≥ 80, approximate Bayes support ≥ 0.95, and ultrafast bootstrap support ≥ 95. The scale bar represents the number of substitutions per site. Sequences of Laonome sp. and Sabella pavonina Savigny, 1822 obtained from GenBank were used for outgroup rooting.

Figure 7. Light micrographs showing the morphologies of living spionid larvae of genera Boccardia, Boccardiella, and Dipolydora A, B Boccardia proboscidea, dorsal view of accidentally hatched 9 - chaetiger (A) and 15 - chaetiger larvae (B) C Boccardia pseudonatrix, dorsal (left) and ventral (right) view of accidentally hatched 10 - chaetiger larvae D-F Boccardia sp. 1, dorsal view of 9 - chaetiger (D) and dorsal (E) and ventral view (F) of 17 - chaetiger larvae G Boccardia sp. 2, dorsal view of 15 - chaetiger larva H, I Boccardiella hamata, dorsal view of 16 - chaetiger (H) and 18 - chaetiger larvae (I) J, K Dipolydora bidentata, dorsal view of 13 - chaetiger (J) and 18 - chaetiger larvae (K) L Dipolydora cf. commensalis, dorsal view of 21 - chaetiger larva M, N Dipolydora giardi, dorsal view of 19 - chaetiger (M) and lateral view of 21 - chaetiger larvae (N) O Dipolydora cf. socialis, dorsal view of 18 - chaetiger larva P Dipolydora sp., dorsal view of 7 - chaetiger larva. Scale bars: 300 μm.