Amphiglena nishii, Capa & Rouse, 2007

Capa, Maria & Rouse, Greg W., 2007, Phylogenetic relationships within Amphiglena Claparède, 1864 (Polychaeta: Sabellidae), description of five new species from Australia, a new species from Japan, and comments on previously described species, Journal of Natural History 41 (5 - 8), pp. 327-356 : 348-350

publication ID	https://doi.org/ 10.1080/00222930701194938
persistent identifier	https://treatment.plazi.org/id/9C3F6324-FFCE-FFEC-FE4F-EFC429E4324A
treatment provided by	Felipe
scientific name	Amphiglena nishii
status	sp. nov.

Treatment

Amphiglena nishii View in CoL sp. nov.

( Figures 4K–N View Figure 4 , 9 View Figure 9 ) Amphiglena pacifica ( Rouse and Gambi 1997, 1998a; Fitzhugh and Rouse 1999; not Amphiglena pacifica Annenkova, 1934 ).

Material examined

Japan, Misaki. Holotype: SAM E3638 View Materials , intertidal algal mats, 139 ° 36980 E, 35 ° 099 N, 20 May 1998. Paratypes: SAM E3639 View Materials , same sample (five specimens), AM W30485 , same sample (one specimen, SEM) .

Description

Holotype 1.8 mm long, branchial crown 1 mm long, with eight thoracic and 15 abdominal chaetigers. Crown is about half body length, with four pairs of radioles with about nine pairs of alternating long pinnules; tip of radioles is longer than pinnules ( Figure 9A View Figure 9 ). Dorsal lips about one-quarter of length of crown ( Figure 9C View Figure 9 ). Anterior peristomial ring short, only visible ventrally ( Figure 9B, C View Figure 9 ). Posterior peristomial ring of even height all around, slightly enlarged ventrally on margins of mid-ventral groove; collar absent ( Figure 9B, C View Figure 9 ). Ventral basal flanges present from basal pinnules of ventralmost radioles to middle of posterior peristomial ring ( Figure 9B View Figure 9 ). Peristomial eyes brown and circular. Thorax longer than wide with quadrangular similarly sized ventral shields. Two notochaetae in first thoracic chaetiger, one narrowly hooded and another broadly hooded ( Figure 9D View Figure 9 ). Rest of chaetigers with one superior broadly hooded thoracic notochaeta, and two inferior thoracic paleate notochaetae, in a single row ( Figure 9D View Figure 9 ). Second to 8th chaetiger with four to six thoracic uncini per fascicle, similar in size, with about four rows of small, similarly sized teeth, above the main fang, arranged in the upper half of uncini ( Figure 9D, E View Figure 9 ); breast well developed, as long as the tip of main fang, handles short ( Figure 4K, L View Figure 4 ). Companion chaetae geniculated, with straight shaft and elongate mucro with several basal teeth of similar size ( Figure 9D, E View Figure 9 ). About four abdominal uncini per torus with several rows of small teeth of similar size above main fang ( Figure 9F, G View Figure 9 ), breast well developed, handle short, about half of uncini width ( Figure 4M, N View Figure 4 ). Three broadly hooded abdominal neurochaetae in each fascicle ( Figure 9G View Figure 9 ). Pygidial eyes as four to six orange-brown spots on each side of lateral margins of peristomium. Statocysts not seen. Tube unknown.

Variation

Length of the body 0.8–3 mm, branchial crown 0.2–1 mm. Four specimens with eight thoracic chaetigers and one with six, the number of abdominal chaetigers is between 10 and 36. Two juvenile specimens with five and eight thoracic and one and three abdominal chaetigers, respectively. The crown is one-third to half the length of the body, with four or five radioles with scarce alternating and very long pinnules arranged in the proximal part of radioles. None of the specimens have gametes.

Remarks

This species is characterized by short thoracic uncini in thoracic and abdominal chaetigers with a broad and long breast. It also has a short posterior peristomial ring of even height, only slightly projecting forward on both sides of the mid-ventral incision. The most similar species is A. maiteae sp. nov. but they differ in the length of the uncinal handles. Amphiglena nishii sp. nov. differs from the other species of the genus recorded in Japan, A. pacifica , in the length of the thoracic and abdominal uncini handles, which are both much shorter in the new species. The uncinal breast is also shorter and narrower in both thoracic and abdominal uncini of A. pacifica and the abdominal uncini have a long neck ( Annenkova 1934; Rzhavsky 1995). The data on reproductive mode and sperm morphology given by Rouse and Gambi (1997, 1998b) and Fitzhugh and Rouse (1999) for A. pacifica refer to A. nishii sp. nov. and not to A. pacifica Annekova.

Etymology

It is our pleasure to name this species for Dr Eijiroh Nishii, Yokohama National University, Japan in recognition of his valuable contributions to polychaete taxonomy.