Chaetozone PAP sp657

Family:

Cirratuldae

Genus:

Chaetozone

Species binomial name, or informal name:

Chaetozone PAP sp657

Authority:

Eulogio Soto & Gordon Paterson

Material Examined:

16 individuals examined. Porcupine Abyssal Plain (Challenger 79, May 1991 1 individuals; Challenger 111, April 1994 2 individuals; Discovery 222, September 1996 1 individuals; Discovery 226, March 1997 5 individuals; Discovery 229, July 1997 4 individuals; Discovery 231, March 1998 2 individuals and Discovery 237, September 1998 1 individuals).

Voucher: Ocean Basin:

NE Atlantic

Voucher: Cruise/Expedition:

BENGAL

Voucher: Location:

48º N 16 º W

Voucher: Depth:

4835 m

Voucher: Repository:

NHM, London

Description:

Chaetozone PAP sp5 sp657 Description: Body shape in lateral view: same shape throughout. Overall body shape in dorsal view: tapering posteriorly. Thoracic body shape in dorsal view: widest just distal to buccal region. Thoracic profile in TS: body cylidrical in TS. Total number of chaetigers: less than 50 chaetigers. Pigmentation of body (in preservative): no obvious pigmentation. Parapodia shape: not obviously elevated. Methyl green pattern: Uniform and diffuse.
Prostomium shape: conical with pointed/rounded tip. Lateral view of prostomium: prostomium pointed forward. Nuchal organ: not observed. Sub-dermal eyes: not present. Annulations on peristomial region: three annulations. Dorsal crest on prostomium (lateral view): absent. Dorsal ridge: absent. Position of the dorsal tentacles: on persistomium. Very long thoracic bottle-brush notochaetae: present. Very long thoracic bottlebrush neurochaetae: absent. Bottle-brush chaetal length: 5 chaetigers long. Thoracic bottle-brush notochaetae starting at chaetiger 1. Number of thoracic notochaetae per fascicle: 6 chaetae. Number of thoracic neurochaetae per fascicle: 4–6 chaetae. Thoracic neurochaetal type: all capillaries.
Intermediary body region between thorax and abdomen: present. Mid-section with swollen region: no swollen region posterior to thoracic chaetigers. Intermediary body region length: 2 chaetigers. Intermediary body region chaetae: bottle-brush’ chaetae present. Abdominal segment shape: moniliform - rounded and constricted between segments. Groove on abdominal segments: grooves absent. Acicular spine shape: acicular without edge. Length of abdominal acicular spines: less than half a segment width. Maximum number of abdominal modified chaetae in notopodia: 10 chaetae. Maximum number of abdominal modified chaetae in neuropodia: 10 chaetae. Abdominal acicular spines: present, both. Abdominal cinctures of spines in transverse section: full cinctures no gaps between fascicles. Companion chaetae: present as thin capillary. TS shape of abdominal segments: rounded, circular. Description of modified chaetae: Straight to slightly curved; relatively thick with pointed tips. Pygidium: anus surrounded by lobes of similar size.
Habitat: Habitat: sediment dwelling.

Remarks:

This species mainly differs from other PAP Chaetozone species already described in thoracic body shape, shape of the prostomium, buccal region length, number of chaetigers with long ’bottle-brush’ chaetae, palp scars location, acicular spines forming complete cinctures and abdominal region shape.

Illustrations:

Chaetozone PAP 657. Top left: Whole specimen. Top right: Abdominal segments. Bottom left: close up of thoracic chaetae. Bottom right: pygidium.