Lumbrinerides dayi Perkins, 1979

Miura, Tomoyuki, 2017, Classification and Morphological Variations of the Japanese Species of Lumbrinerides (Annelida: Lumbrineridae), Species Diversity (Auckland, N. Z.) 22 (1), pp. 7-27 : 21-23

Lumbrinerides dayi Perkins, 1979

( Figs 11 , 12 )

Lumbrinerides dayi Perkins, 1979: 421–423 , fig. 1c–e; Miura 1980: 1025–1026, fig. 3B.

Lumbrinerides hayashii Imajima, 1985: 173–174 , fig. 2a–j. Syn. nov.

Material examined. Holotype and paratype of Lumbrinerides hayashii , NSMT-Pol H-195 and NSMT-Pol P-196, respectively, both Wakasa Bay, 10 m, July 1970; 5 paratypes of Lumbrinerides dayi, USNM 55598, Florida, off Panama City, 47 m, coarse carbonate sand, November 1977.

Comparative material. Lumbrineris aberrans Day, 1963 sensu Day (1973) , DMLM 2481, off Beaufort, 5–20 m, 19 April 1965; Lumbrinerides dayi sensu Imajima (1985) : NSMT-Pol 77735, off Shimoda, 60–68 m, 9 November 1981.

Non-type material. ( SOMA) (12 immature, 14 juveniles); ( IMA A) (one female) and IMA B (one male, one juvenile); ( SADO A) Tansei-maru Cruise KT-85-14, Japan Sea , Station F-5 BC-2, (two immature); Station F-5 SM-1 (one immature); Station F-5 SM-2 (one female, one immature) .

Diagnosis. Prostomium up to three times longer than wide ( Fig. 11A ). Two apodous peristomial rings. Six to ten anterior parapodia reduced ( Fig. 11 A–C), thereafter fully developed (posteriorly from chaetigers 10–12) ( Fig. 11D, E ). Maxillae I with two well-defined accessory teeth, maxillae II with three teeth ( Fig. 11F ). Large specimens with more than 3 concentric lines on mandibles considered as adults ( Fig. 11G ). Bidentate simple hooded hooks beginning on chaetigers 1–6 ( Fig. 11H ).

Variations. The prostomium length to width proportion in Japanese specimens varied between 1.14–2.23, slightly less than given in the original description, 1.2–3.0. The types of L. hayashii are immature and lack considerable posterior portions of the body. The chaetae were generally well preserved and their distribution in the type specimens and other material could be examined in detail ( Fig. 12 ). Specimens collected off Imabetsu and off Soma and referred to this species had two accessory teeth on maxillae I, ten anterior reduced parapodia and simple hooks on chaetiger 1–3, being more intact in chaetal possession. The limbate chaetae started on the first chaetiger as two per parapodium in most specimens, the number becoming three on ca. parapodia 10 to 30–35, subsequently reducing to two on more posterior parapodia and one on ca. parapodia 80–130 (possibly depending on specimen size), and eventually zero on well posterior parapodia ( Fig. 12 ). Hooks numbered two on parapodia 1–10 or somewhat later, one on ca. parapodia 10 to 30–35, and two or three on more posterior parapodia ( Fig. 12 ).

Remarks. In 26 specimens (12 immature, 13 juvenile and one damaged) collected from off Soma, the number of anterior reduced parapodia varied from seven to nine ( Fig. 2 ), but fully developed parapodia were apparent on chaetiger 10–12, as given in the original description of L. dayi by Perkins (1979) and also in the description of L. hayashii by Imajima (1985). As no significant morphological differences were apparent in other characters between these two species, they are synonymized here. One of two Shimoda specimens recorded as L. dayi by Imajima (1985) was reexamined and its identification confirmed.

Biological notes. The spawning season of L. dayi is thought to be in summer, based on the collection of an ovigerous female in August 1983 from off Imabetsu and another in September 1985 from south part of the Sado Strait.

Distribution. Wakasa Bay (10m), off Imabetsu (18– 21 m), off Soma (38–46 m), South Sado Strait (52–58 m), on sandy substrates, Japan; off Panama City (47 m), off Beaufort (5–20 m), Atlantic coast of US.

Figures

Fig. 11. Lumbrinerides dayi Perkins, 1979, based on specimens from off Soma, in 38–46 m depth. A, dorsal view of anterior end of specimen collected from sandy bottom (38m depth); B, anterior view of parapodium 1; C, anterior view of parapodium 7 on left side; D, anterior view of parapodium 15; E, anterior view of parapodium 20; F, maxillae; G, mandibles; H, hook from a posterior parapodium.

Fig. 12. Chaetal distribution pattern in type specimens for Lumbrinerides hayashii Imajima, 1985 and Japanese comparative specimens identified as Lumbrinerides dayi Perkins, 1979 from off Soma, in 38–46 m depth. Numbers of hooks (closed circle) and limbate chaetae (open circle) per parapodium were plotted for each parapodium from the first to the last chaetigers of fragmented specimens.

Fig. 2. Frequency histograms (%) for each local sample containing more than 20 specimens (treated initially as operational taxonomic units). Characters assessed included mean number of accessory teeth on maxilla I plates, number of anterior reduced parapodia, prostomium length to width proportion, chaetiger number on which first hooks present, number of concentric lines on mandibles and body width (mm). White bars represent juveniles or growing phase; black bars represent specimens grown sufficiently for use for taxonomic purposes.