Dipolydora sp.

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

Dipolydora sp. Fig. 7P

Larval morphology.

Overall body shape slender. Prostomium small and rounded anteriorly. Anterior margin of prostomium has weak yellow-brown pigment. Three pairs of black eyes present in transverse row, most lateral pairs double-eyes. Black pigmentation on lateral peristomium absent. A pair of dorsal black spots present on chaetiger III onwards. A small medial spot of black pigment on posterior margin of chaetiger III. Some black pigment occurs on pygidium. Ventral pigment absent. Gastrotrochs occur on chaetigers III and V.

Remarks.

No adult individuals of this species were collected in the present study. The 18S and 16S rRNA gene sequences obtained from larvae in the present study did not match any available Dipolydora sequences. As the larvae specimens formed a monophyletic clade with the other Dipolydora species (excluding D. armata , D. capensis 1GG, D. cf. commensalis , and D. quadrilobata ) with robust statistical supports (Figs 2 , 3 ), this species was referred to Dipolydora sp.

Figures

Figure 2. Maximum Likelihood tree inferred from nuclear 18 S and mitochondrial 16 S rRNA gene sequences of spionids obtained from Japan in the present and previous studies (provided in Table 1). The gene sequences of adult and larval spionid polychaetes 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 DDBJ / EMBL / GenBank were used for outgroup rooting.

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.