Pavelius makranensis Reuscher & Fiege, 2016, sp. nov.
Creators: name: Reuscher, Michael G.
name: Fiege, Dieter
Publisher: name: Zenodo
Year: 2016
Subjects: Biodiversity
Taxonomy
Animalia
Annelida
Polychaeta
Terebellida
Ampharetidae
Pavelius
Pavelius makranensis

description: Pavelius makranensis sp. nov.
(Figs 5 A–D; 6A–E; 7C)
Specimens examined. Holotype: SMF 24139, Flare 2 cold seep, Makran accretionary prism, continental margin of Pakistan, 24°50.753’N 63°01.439’E, 1025 m, M 74/3, ROV Dive 181, push core, 6 November 2007 (cs, male). Paratype: SMF 24140, same station data as holotype (1 cs, female). Paratype: SMF 24141, same station data as holotype (1 cs, female). Paratypes: SMF 24142, Flare 2 cold seep, Makran accretionary prism, continental margin of Pakistan, 24°50.829’N 63°01.419’E, 1038 m, M 74/3, ROV Dive 180, sampling net, 5 November 2007 (1 cs, male). Paratypes: SMF 24143, Flare 2 cold seep, Makran accretionary prism, continental margin of Pakistan, 24°50.829’N 63°01.419’E, 1038 m, M 74/3, ROV Dive 180, sampling net, 5 November 2007 (4 cs, 3 af, 4 females, 3 males, plus 3cs used for SEM, stub-nos. 1199–1201).
Additional material examined. SMF 24144, Flare 2 cold seep, Makran accretionary prism, continental margin of Pakistan, 24°50.829’N 63°01.419’E, 1038 m, M 74/3, ROV Dive 180, sampling net, 5 November 2007 (2af, 1 female, 1 male). Another specimen from the same station was used for DNA analysis.
Description. Length 11.7 mm, width 1.6 mm. Prostomium with lateral incisions delimiting middle section, not reaching anterior end; prostomial glandular ridges absent; paired lateral dark pigment stripes in prostomium (Fig. 5 A). Buccal tentacles smooth. Four pairs of smooth cirriform branchiae arranged in one transverse row in segment III, not separated by median gap; branchiae with very densely arranged thick branchiophores, tapering distally; second outermost branchiae of transverse row originating from segment II, outermost branchiae of transverse row originating from segment III, innermost branchiae of transverse row originating from segment IV, second innermost branchiae of transverse row originating from segment V (Fig. 7 C). Segment II with small chaetae, resembling capillary notochaetae of following segments; chaetae of segment II emerging from notopodia like humps, located more ventrally than notopodia (Fig. 5 A). Notopodia with capillary chaetae (Fig. 6 A) from segment III, present in 15 chaetigers; first pair of notopodia smaller than following ones; first three pairs of notopodia slightly elevated dorsally above following notopodia; notopodia without cirri. Large nephridial papillae above notopodia of first unciniger (Figs. 5 A, 6B). Neuropodial tori with uncini from segment VI, present in 12 thoracic uncinigers; tori without cirri. Continuous ventral shields conspicuous to thoracic unciniger 10, faint in thoracic unciniger 11. Two intermediate uncinigers (Fig. 5 B). Sixteen abdominal uncinigers. Rudimentary notopodia present as small papillae in intermediate uncinigers and first abdominal unciniger (Fig. 5 B), absent in remaining abdominal uncinigers. Pinnules without dorsal cirrus (Fig. 5 C). Pygidium with terminal anus but without anal cirri. Thoracic uncini with unpaired tooth on top and paired median teeth over rostral tooth and basal prow, framed by small lateral teeth (Fig. 6 C, D). Abdominal uncini with about seven teeth over rostral tooth and basal prow (Fig. 6 E). Tube made of dark grey clay.
Remarks. The large nephridial papillae are presumably only present in male specimens. They were lacking in every specimen that contained eggs and vice versa.
The prostomial dark pigment stripes in the holotype and several paratype specimens probably belong to nuchal organs. In some paratype specimens the area behind the lateral incisions of the prostomium lacked the dark pigment. Instead, they appeared to be brightly colored nuchal organs (Fig. 5 D). About half of the complete paratype specimens had ventrolateral papillae in their pygidia, while the other half and the holotype did not. It seems that Pavelius makranensis sp. nov. can contract the pygidium and withdraw the anal papillae. The only congener Pavelius uschakovi Kuznetsov & Levenstein, 1988 has 21 abdominal uncinigers (assuming that the first two of the 23 abdominal segments mentioned in the original description are actually intermediate uncinigers), five more than in the new species. P. makranensis sp. nov. has notopodial rudiments in the intermediate uncinigers and the first abdominal unciniger, whereas they are lacking in P. uschakovi. Finally, the abdominal uncini of P. uschakovi were described with five teeth. The new species has abdominal uncini with seven teeth. The type specimen of P. uschakovi was not available for examination because it is lost (Budaeva, pers. comm.).
The new species had been tentatively identified as Pavelius uschakovi in an ecological study of the Makran accretionary prism (Fischer et al. 2011). They noted that the species dominated a transitional area between a central microbial mat and a peripheral vesicomyid clam bed.
The only other described congener P. uschakovi has been recorded from the Paramushir gas hydrate seep in the Sea of Okhotsk and from gas hydrates on the Cascadia margin (Sahling et al. 2002). A presumably undescribed species was recorded from the coast off Natuna Island in the China Sea (Al-Hakim & Glasby 2004). No mention of gas hydrate seeps was made in the latter case.
Unfortunately, DNA sequencing for three genes, i.e. COI, 16S rDNA and 18s rDNA, did not yield contiguous sequences. Possible explanations might be insufficient fixation or subsequent storage of samples under ambient conditions.
Etymology. The new species is named after its sampling location, the Makran accretionary prism.
Distribution. Exclusively known from cold seeps of the Makran accretionary prism off the coast of Pakistan.
description: Published as part of Reuscher, Michael G. & Fiege, Dieter, 2016, Ampharetidae (Annelida: Polychaeta) from cold seeps off Pakistan and hydrothermal vents off Taiwan, with the description of three new species, pp. 197-208 in Zootaxa 4139 (2) on pages 204-206, DOI: 10.11646/zootaxa.4139.2.4, http://zenodo.org/record/262112