Polygordius arafura , Avery, Lynda, Ramey, Patricia A. & Wilson, Robin S., 2009

Avery, Lynda, Ramey, Patricia A. & Wilson, Robin S., 2009, New Polygordiidae (Polychaeta) from the Australian region, Zootaxa 2068, pp. 59-68: 61-63

publication ID

http://doi.org/ 10.5281/zenodo.187027

persistent identifier

http://treatment.plazi.org/id/0394223C-FFAF-4F67-FF38-FC999A6EFA76

treatment provided by

Plazi

scientific name

Polygordius arafura
status

sp. nov.

Polygordius arafura  sp. nov.

Figure 1View FIGURE 1 A –F

Material examined. Holotype: Australia: Northern Territory. Arafura  Sea: Stn SS05/ 2005 007GR011, 9 ° 50.126 ' S 135 ° 17.766 ' E, 4 May 2005, 83 m, calcareous poorly-sorted muddy fine sand, ( NTM W 22253View Materials). Paratypes: same data as for holotype, spirit specimens, 1 paratype NTM W22254View Materials, 1 complete paratype and 3 fragments NTM W 20934View Materials. Paratypes: Australia, Northern Territory, Arafura  Sea: Stn SS05/ 2005 002GR002 9 ° 47.986 ' S 135 ° 22.007 ' E, 91.2 m, 1 May 2005, 4 paratypes: NTM W 22248View Materials, NTM W 22249View Materials, NTM W 22250View Materials, NTM W 22251View Materials, and one SEM stub paratype NTM W 22252View Materials; 2 paratypes, MV F 165642, F 165643; 1 paratype, USNM 1121878. One paratype: Australia: Northern Territory. Arafura  Sea: Stn SS05/ 2005 012GR019, 9 ° 47.593 ’ S 135 ° 16.636 ’ E, 5 May 2005, 85 m, muddy sand, USNM 1121879.

Non-type material: Australia: Northern Territory. Arafura  Sea: Stn SS05/ 2005 012GR019, 9 ° 47.593 ’ S 135 ° 16.636 ’ E, 5 May 2005, 85 m, muddy sand, 2 spirit specimens ( NTM W 20939View Materials); Stn SS05/ 2005 005GR007, 9 ° 50.47 ’ S 135 ° 16.099 ’ E, 4 May 2005, 80 m, muddy sand, 1 spirit specimen and 2 specimens on one SEM stub ( NTM W 20941View Materials); Stn SS05/ 2005 002BS002, 9 ° 47.947 ’ S 135 ° 22.024 ’ E, 1 May 2005, 92 m, moderately sorted calcareous medium sand, 1 specimen ( NTM W 20936View Materials); Stn SS05/ 2005 006GR009, 9 ° 50.356 ’ S 135 ° 20.888 ’ E, 4 May 2005, 87 m, poorly-sorted muddy fine calcareous sand, 1 specimen ( NTM W 20937View Materials); Stn SS05/ 2005 011GR018, 9 ° 47.768 ’ S 135 ° 16.935 ’ E, 5 May 2005, 84 m, muddy sand, 1 specimen ( NTM W 20942View Materials); Stn SS05/ 2005 009GR015, 9 ° 49.294 ’ S 135 ° 19.599 ’ E, 4 May 2005, 83 m, 5 Y 4 / 2, poorly-sorted calcareous, muddy medium sand, 1 specimen ( NTM W 20940View Materials); Stn SS05/ 2005 003GR005, 9 ° 52.788 ’ S 135 ° 21.891 ’ E, 4 May 2005, 69 m, Sandy Mud, 1 specimen and wholemount microslide ( NTM W 20938View Materials); Stn SS05/ 2005 010GR017, 9 ° 48.774 ’ S 135 ° 15.412 ’ E, 5 May 2005, 82 m, sandy mud GLEY 1 4 / 10 Y, 1 specimen and wholemount microslide ( NTM W 20935View Materials).

Distribution. Australia. Northern Australia, Arafura  Sea, Gulf of Carpentaria ( Fig. 1View FIGURE 1 F). Habitat marine, shelf 69–92 m, mostly from poorly-sorted sediments.

Description. Size range of material examined 2.4–11.6 mm long, 0.08–0.18 mm wide (n = 15), inflated pygidial region about 1.2 times maximum body width.

Prostomium conical (0.06–0.12 mm long), pointed at tip (Fig. l A). Eyes absent. Paired antennae 0.04–0.06 mm long, almost attached to each other at the base, and remain parallel for some distance (Fig. l B). Ratio of antenna to prostomium length 0.5–0.86. Head fold deep (Figure l A). Dimensions of holotype given in Table 2.

Pygidium cylindrical, minimally inflated (about 1.2 times body width), pygidial glandular pads absent (Fig. l C, confirmed by examination of whole mounts using compound microscope). Pygidial appendages absent. Anal opening central; anal lobes present; 7–8 approximately equal-sized lobes (Fig. l D). Epidermis of pygidium lacking cilia ( Fig. 1View FIGURE 1 E). Neither eggs nor sperm could be seen in any specimen examined in temporary or permanent whole body mounts.

Discussion. Table 1 groups all known Polygordius  species based on presence or absence of pygidial glands, and subterminal or terminal pygidial appendages. Polygordius arafura  sp. nov. is similar to three other species that also lack pygidial glands and pygidial appendages. Of these Polygordius uroviridis  is easily distinguished from Polygordius arafura  sp. nov. by its inflated or bulb-like pygidium, the presence of eyes, and a dark band of pigment encircling the middle region of the pygidium. Polygordius arafura  sp. nov. is most similar to Polygordius jouinae  and Polygordius triestinus Hempelmann, 1906  . Polygordius arafura  sp. nov., has shorter antennae (0.04–0.06 mm) than P. jouinae  (0.10–0.15 mm), and the length ratio of antennae to prostomium is ~ 0.5 for P. arafura  sp. nov. and ~ 1 for P. jouinae  (see also Table 2). Moreover, Polygordius arafura  sp. nov. has a deep head fold while P. j o u i n a e and P. triestinus  have a shallow head fold. Although no head fold has been described for P. jouinae  , examination indicated that the head fold is shallow. Finally, P. jouinae  has a distinctly ciliated pygidial region ( Ramey et al. 2006: 1029 figure 2 F) whereas P.arafura  sp. nov. has the pygidial region bare of cilia ( Fig. 1View FIGURE 1 E). The species description for P. triestinus  is incomplete for many characters ( Table 2) and Ramey et al. (2006) were unsuccessful in locating type material. Moreover, P. triestinus  has not been reported since the original description and is not present in benthic samples taken from the Gulf of Trieste from 1966–2003 ( Ramey et al. 2006).

Etymology. The specific name arafura  is derived from the name of the indigenous inhabitants of the Molluccas, "the people of mountains", a name subsequently also given to the Arafura  Sea, the type locality of P.arafura  sp. nov.

Pygidial appendages Pygidial appendages subterminal Pygidial appendages terminal absent

Pygidial glands / P. antarcticus  P. appendiculatus  P. eschaturus  glandular pads present P. erythrophthalmus  P. k i a r a m a sp. nov. P. eschaturus brevipapillosus 

P. lacteus  P. l e o P. madrasensis 

P. neapolitanus 

P. pacificus 

P. pacificus floreanensis 

P. triestinus  j

Pygidial glands / P. arafura  sp. nov. glandular pads absent P. jouinae 

P. triestinus  h

P. uroviridis 

Undetermined P. vil lot  i P. ijimai 

NTM

Northern Territory Museum of Arts and Sciences

USNM

Smithsonian Institution, National Museum of Natural History