Pectinaria crenulatus ( Sun & Qiu, 2012 )

Zhang, Jinghuai, Hutchings, Pat & Qiu, Jian-Wen, 2022, Pectinariidae (Annelida, Polychaeta) from the coastal waters of China, with description of new species and new records, Zootaxa 5151 (1), pp. 1-74 : 62-63

Pectinaria crenulatus ( Sun & Qiu, 2012)

Type locality. Hong Kong, China

Figs 36 , 40

Lagis crenulatus Sun & Qiu, 2012: 61–68 , Figs 2–4 in Sun & Qiu (2012).

Material examined. Paratype: AM W.38672–38674, AM W.38676, and AM W.38679–38680, 6 specs, Mai Po Inner Deep Bay , Ramsar Site, the northern Yellow Sea, Hong Kong, 114°02'00.0"E 22°30'00.0"N, intertidal, mud, coll. Y. Sun & J Qiu, Hong Kong Baptist University, February 2009 . AM W.38681–38682, 2 specs, Mai Po Inner Deep Bay Ramsar Site, the northern Yellow Sea, Hong Kong, 114°02'00.0"E 22°30'00.0"N, intertidal, mud, coll. Y. Sun & J. Qiu, Hong Kong Baptist University, May 2010 .

Non type material examined. SCSMBC030941, SCSMBC030942, and SCSMBC030943, 3 specs, Mai Po Inner Deep Bay Ramsar Site, the northern Yellow Sea, Hong Kong, 114°02'00.0"E 22°30'00.0"N, intertidal, mud, coll. Y. Zhang & J Qiu, Hong Kong Baptist University, May 2010 .

Description. Refer to Sun & Qiu (2012). Some changes from original descriptions are as following: Cephalic veil free from operculum; pair of ear-shaped lobes adjacent to both sides of dorsal base of cephalic veil between cephalic veil and segment 1 ( Fig. 40 ).

Distribution. Only known from type locality ( Hong Kong, China) ( Fig. 36 ).

Habitat. Collected from intertidal mud.

Remarks. Pectinaria crenulatus ( Sun & Qiu, 2012) is easily distinguished from other pectinariids from Chinese waters by the lack of branchiae on segments 3–4. Fauvel (1932) and Sun & Qiu (2012) describe the cephalic veil of the two species Lagis abranchiata ( Fauvel, 1932) and L. crenulatus Sun & Qiu, 2012 where it is partially connected to the operculum. This character is questionable. We examined specimens of L. crenulatus from Hong Kong collected from the type locality, and found a pair of ear-shaped lobes adjacent to both sides of the base of the cephalic veil between cephalic veil and segment 1, and which differs from the pair of ear-shaped lobes of Lagis which are present posterior to the cephalic veil between the buccal cavity and segment 1 (Zhang et al. 2019, Fig. 3 ). Based on the cephalic veil being free from operculum and a pair of ear-shaped lobes adjacent to both sides of base of cephalic veil between cephalic veil and segment 1, we are proposing that L. crenulatus be moved to the genus Pectinaria . The distribution of chaetae is the same as P. plurihamus with capillary notochaetae on segments 5–20 and neurochaetae (uncini) on segments 8–19, but P. plurihamus has branchiae on segments 3–4 unlike P. crenulatus . Pectinaria crenulatus can be distinguished from another species Lagis abranchiata ( Fauvel, 1932) described from Cochin, Ernakulam, India which is similar in lacking branchiae on segments 3–4, but the lateral margins of scaphe of P. crenulatus are flat, crenulated and not ovate, whereas those of Lagis abranchiata have rounded lobes.

Molecular results

The phylogenetic tree is based on the concatenated dataset of five Sanger-sequenced genes (two mitochondrial regions: COI and 16S; three nuclear regions:18S, 28S and H3) which consisted of 146 sequences including 13 species of all recorded valid genera of pectinariids and two outgroups: one of the family Trichobranchidae , another of the family Arenicolidae ( Fig. 41 , Table 1). The Bayesian tree was used to analyse the phylogenetic relationship of Pectinariidae with good support (posterior probability>61%). The pectinariid clade is monophyletic and is well supported ( Fig. 41 ). Petta pusilla has the closest relationship with outgroups, and forms a well support clade with other species of pectinariids. The two new species Pectinaria lizhei n. sp. and Pectinaria dayaensis n. sp. from the coastal waters of China are well supported with a sister relationship. The two species clade is sister to Pectinaria torquata from the northern South China Sea and they form a well supported clade ( Pectinaria torquata ( P. lizhei n. sp. - P. dayaensis n. sp.)). The two species Lagis crenulatus from waters of Hong Kong and Pectinaria gouldii from Egypt Lane, Fairhaven, MA ( USA) form a weakly supported clade (posterior probability 77%). ( Lagis crenulatus - Pectinaria gouldii ) and ( P. torquata ( P. lizhei n. sp. - P. dayaensis n. sp.)) form a weakly supported clade (posterior probability 81%). Two species, Lagis koreni from the English Channel and L. bocki from offshore sites of west-northern Pacific Ocean form a well supported clade. Two species Amphictene alata and A. jianqingi n. sp. from the coastal waters of China are well supported with a sister relationship ( Amphictene alata - A. jianqingi n. sp.) and ( Lagis koren-L. bocki ) are sister groups and are also well supported. Amphictene auricoma and (( Amphictene alata - A. jianqingi n. sp.) ( Lagis koren - L. bocki )) form a supported clade (posterior probability 85%). (( Lagis crenulatus - Pectinaria gouldii ) ( P. torquata ( P. lizhei n. sp. - P. dayaensis n. sp.))) and ( Amphictene auricoma (( A. alata - A. jianqingi n. sp.) ( Lagis koren - L. bocki ))) form a well supported clade (posterior probability 97%). Lagis plurihumus and ((( Lagis crenulatus - Pectinaria gouldii ) ( P. torquata ( P. lizhei n. sp. - P. dayaensis n. sp.))) ( Amphictene auricoma (( A. alata - A. jianqingi n. sp.) ( Lagis koren-L. bocki )))) form a supported clade (posterior probability 85%). Cistenides granulata and ( Lagis plurihumus ((( Lagis crenulatus - Pectinaria gouldii ) ( P. torquata ( P. lizhei n. sp. - P. dayaensis n. sp.))) ( Amphictene auricoma (( A. alata - A. jianqingi n. sp.) ( Lagis koren-L. bocki ))))) form a weakly supported clade (posterior probability 65%). Three species of Amphictene : A. auricoma , A. alata and A. jianqingi n. sp. do not form a clade. Four species of Lagis : L. koren , L. bocki , L. crenulatus and L. plurihumus also do not form a clade. Four species of Pectinaria : P. gouldii , P. torquata , P. dayaensis n. sp. and P. lizhei n. sp. also do not form a clade. The three new species Amphictene jianqingi n. sp., Pectinaria lizhei n. sp. and P. dayaensis n. sp. are all supported by this analyse.

Figures

FIGURE 2. Amphictene alata Zhang, Zhang & Qiu, 2015 Methyl Green stained body (SCSMBC030866): A. Dorso-lateral view of distorted entire body; B. Ventral view of distorted entire body; C. Dorsal view of anterior end; D. Lateral view of anterior end; E. Ventral view of posterior end; F. Lateral view of posterior end; G. Ventral view of posterior end; H. Dorsal view of posterior end; I. Scaphal hooks. Abbreviations: af, anal flap; br, branchiae; bt, buccal tentacles; cv, cephalic veil; dlp, dorsolateral pads; dls, dorsal lobe of scaphe; nep, neuropodium; noc, notopodial chaetae; op, operculum; or, opercular rim; p, paleae; s, segment; sc, scaphe; sh, scaphal hooks; tc, tentacular cirri; vl, ventral lappet.

FIGURE 3. Relationship between body width and body length, number of pairs of paleae, number of cirri on cephalic veil, number of pairs of scaphal hooks, number of cirri on opercular rim, for Amphictene alata Zhang, Zhang & Qiu, 2015.

FIGURE 4. Amphictene jianqingi n. sp. Methyl Green stained body of Holotype (SCSMBC030870): A. Ventral view of entire body; B. Dorsal view of entire body; C. Dorsal view of anterior end; D. Ventral view of anterior end; E. Dorsal views of scaphe; F. Lateral view of posterior end; G. Anal flap; H. Dorsal views of posterior end; I. left hooks.Abbreviations: ac, anal cirrus; af, anal flap; br, branchiae; bt, buccal tentacles; cv, cephalic veil; dcs, dorsal cirrus of scaphe; dlp, dorso-lateral pad; dls, dorsal lobe of scaphe; noc, notochaetae; op, operculum; or, opercular rim; p, paleae; s, segment; sc, scaphe; sh, scaphal hooks; tc, tentacular cirri.

FIGURE 36. Map illustrating the distribution of Pectinaria plurihamus (Choi, Jung & Yoon, 2017) and P. crenulatus (Sun & Qiu, 2012) in the coastal waters of China.

FIGURE 40. Pectinaria crenulatus (Sun & Qiu, 2012) (SCSMBC030943): A. Lateral view of entire body; B. Tube; C. Lateral view of anterior end; D. Lateral view of posterior end. Abbreviations: af, anal flap; an, anus; bt, buccal tentacles; cv, cephalic veil; dlp, dorso-lateral pad; lel, lateral ear-shaped lobe; or, opercular rim; p, paleae; s, segment; sc, scaphe; tc, tentacular cirri; vl, ventral lappet.

FIGURE 41. Bayesian phylogenetic tree of the family Pectinariidae based on multigene sequences (COI, 16S rDNA, 18S rDNA, 28S rDNA and H3), including 13 species of pectinariids and two outgroups (one of the family Trichobranchidae, another of the family Arenicolidae). Numbers above nodes are posterior probabilities.