Ampharete ampullata, Imajima, Minoru, Reuscher, Michael G. & Fiege, Dieter, 2012

Imajima, Minoru, Reuscher, Michael G. & Fiege, Dieter, 2012, Ampharetidae (Annelida: Polychaeta) from Japan. Part I: The genus Ampharete Malmgren, 1866, along with a discussion of several taxonomic characters of the family and the introduction of a new identification tool, Zootaxa 3490, pp. 75-88 : 79-80

Ampharete ampullata sp. nov.

( Figs. 1 A–H; 6A)

Specimens examined. Holotype NSMT-Pol. H 545, Tomioka Bay, Amakusa, 32°31.5’N, 130°02.2’E, intertidal zone, 10.1963. Paratypes: NSMT-Pol. P 546, same locality as holotype (1 cs). SMF 21641, off Eni, Boso Peninsula, 35°01.0’N, 140°04.6’E – 35°01.3’N, 140°05.1’E, 77–83 m, KT-76-16, St. C-2, 9.1976 (6 cs). Additional specimens: Sagami Bay, 35°08.0’N, 139°35.5’E – 35°07.8’N, 139°35.6’E, 73 m, St. 19, 9.1979 (2 cs); 35°00.0’N, 139°40.2’E – 35°00.0’N, 139°40.3’E, 97–108 m, Shin’yo-maru, St. 3, 10.2003 (1 cs). Off Shimoda, 34°44.9’N, 139°02.2’E – 34°45.0’N, 139°01.9’E, 57–85 m, NSMT, St. 5, 10.1981 (1 af); 34°41.0’N, 139°00.8’E – 34°40.4’N, 139°02.5’E, 97–106 m, NSMT, St. 26, 11.1981 (2 cs).

Description. Length 9 mm, width 1 mm. Prostomium with middle lobe delimited by incision, without glandular ridges or eyes. Buccal tentacles without groove, with 2 ventrolateral rows of thick pinnae; tips of pinnae covered by tufts of cilia ( Fig. 1 A–D). 4 pairs of annulated, cirriform branchiae in fused segments II + III; 3 pairs of branchiae in transverse line, separated by wide median gap, 4th pair shifted caudally between 2nd outermost and innermost branchiae of transverse row; branchiae of segment II in 2nd outermost position of transverse row, branchiae of segment III in outermost position of transverse row, branchiae of segment IV in innermost position of transverse row, branchiae of segment V shifted caudally ( Figs. 1 A, B; 6A). Chaetae in fused segments II + III of same length as regular notochaetae, but thinner. Notopodia with limbate capillary notochaetae from segment IV, present in 13 chaetigers ( Fig. 1 E). Neuropodial tori with uncini from segment VI, present in 11 thoracic uncinigers. Cirri and papillae in thoracic parapodia absent ( Fig. 1 B). Continuous ventral shields present to thoracic unciniger 9. Elevated or modified notopodia absent. 2 intermediate uncinigers. 12 abdominal uncinigers. Glandular pads above pinnules in intermediate and abdominal uncinigers absent. Pinnules with cirriform dorsal cirri ( Fig. 1 F). Pygidium with terminal anus, anal cirri lacking (presumably broken off). 1 pair of large, bottle-shaped nephridial papillae in segment IV, shifted forwards between innermost branchiae of transverse row in segment III. Thoracic uncini with 3 teeth in 1 row over basal prow and rostral tooth ( Fig. 1 G). Abdominal uncini with 8 teeth arranged in an arc and 1 median tooth over basal prow and rostral tooth ( Fig. 1 H). Body filled with eggs.

Remarks. The paratype has filiform, lateral anal cirri, suggesting that the anal cirri of the holotype are broken off. The branchiae of the paratype are smooth, rather than annulated. This difference might be caused by the developmental change of ciliation of the branchiae like in other ampharetid genera, such as Sosane Malmgren 1866 sensu Jirkov 2001 , and Anobothrus (personal observations MR).

There are six other valid species of Ampharete with 11 uncinigers, formerly assigned to Sabellides Milne Edwards in Malmgren, 1866. Only 3 of these species have notochaetae in the fused segment II + III. Ampharete borealis ( Sars, 1856) , A. manriquei ( Salazar-Vallejo, 1996) , and A. octocirrata ( Sars, 1835) all have small, rather than large, bottle-shaped nephridial papillae. Ampharete ampullata sp. nov. has 12 abdominal uncinigers, whereas A. borealis has 10, A. manriquei 15, and A. octocirrata 13–15. Ampharete luederitzi ( Augener, 1918) , originally described in the monotypic genus Pterampharete Augener, 1918 that was later synonymized with Sabellides by Day (1964), shares number of thoracic chaetigers and uncinigers, presence of chaetae in segment II, and presence of pinnate tentacles. It differs from the new species by the presence of pinnate branchiae, 9 abdominal uncinigers, larger chaetae in segment II, small nephridial papillae, papilliform dorsal cirri in pinnules, and thoracic uncini with two rows of teeth.

Etymology. The species name refers to the unusual bottle-like shape of the nephridial papillae. Distribution. Off Boso Peninsula, Sagami Bay (Honshu) and Kyushu. All localities are influenced by the warm Kuroshio Current. The species was found from the intertidal to 108 m.

Figures

FIGURE 1. Ampharete ampullata sp. nov.: A: anterior end, dorsal view, 40 x, B: same, lateral view, 40 x, C: distal end of buccal tentacle, 375 x, D: papilla of buccal tentacle, 755 x, E: limbate capillary notochaeta, 755 x, F: abdominal parapodia, 40 x, G: thoracic uncinus, 1100 x, H: abdominal uncinus, 2100 x.