Parasabella sp. 1

Lee, Aria L., Capa, María, Dafforn, Katherine A., Hutchings, Pat A. & Murray, Anna, 2021, New records of non-indigenous Branchiomma and Parasabella species (Sabellidae: Annelida) in South Australia highlight the continuing challenges for sabellid taxonomy, Journal of Natural History 54 (39 - 40), pp. 2647-2673: 2663-2667

publication ID

http://doi.org/ 10.1080/00222933.2020.1862334

persistent identifier

http://treatment.plazi.org/id/03C3F130-FF66-F430-0814-DB030C2437E7

treatment provided by

Marcus

scientific name

Parasabella sp. 1
status

 

Parasabella sp. 1  

( Figures 6–9 View Figure 6 View Figure 7 View Figure 8 View Figure 9 ; Tables 3, 5 and 6)

Material examined

South Australia, North Haven harbour, floating artificial substrate, 34°47 ʹ 9”S, 138° 29 ʹ 15”E, 0.5–1 m, coll GoogleMaps   . 10 June 2015: AM W   .49872, AM W.49873, AM W.49874, AM W.49875, AM W.49871.001 (on SEM pin), AM W.49870.001 (on SEM pin).

Comparative material examined

Parasabella sp. 1   , AM W. 32563 (1), Hutchinson Island , Florida, USA, 27°26 ʹ N, 80°19 ʹ W, 2006; AM W GoogleMaps   . 37041 (1), Cockatoo Island , Sydney Harbour, NSW, Australia, 33°50 ʹ 53”S, 151° 10 ʹ 29”E, 2009 GoogleMaps   .

Parasabella aulaconota, AM W.   37073 (1), Japan, Sagami Bay , Koshigoe near Fujisawa, 35°18 ʹ 20”N, 129°29 ʹ 40”E, collected and identified by E GoogleMaps   . Nishi , 2004   . Parasabella cf. aulaconota, AM W.   37026 (1), AM W. 37027 (1), Darwin Harbour , NT, 12°27’S, 130°51 ʹ E, 2010; AM W GoogleMaps   . 37058 (1), Heron Island , QLD, 23°25 ʹ 57”S, 151°56 ʹ 1.5”E, 2009; AM W GoogleMaps   . 37043 (1), Cape Banks , NSW, 33°59 ʹ 48.1”S, 151°15 ʹ 13.6”E, 2009; AM W GoogleMaps   . 37045 (1), Kurnell , NSW, 34°0 ʹ 33”S, 151°13 ʹ 51”E, 2009; AM W GoogleMaps   . 47004 (1), Port Kembla , NSW, 34°27 ʹ 56.9”S, 150° 56 ʹ 22”E GoogleMaps   . 2014.

Parasabella aberrans, AM W.   37052 (1), Kurnell, NSW, 34°33’S, 151°13 ʹ 51”E.

Size and colour pattern

Specimens measured 9–50 mm in body length (thorax and abdomen) and 2–3 mm in width, with 6–8 thoracic and numerous abdominal chaetigers. Live specimens with pale to white radioles with brown spots on longitudinal axes ( Figure 6 View Figure 6 (a,b)). Body colour varied from pink to greenish-brown, some specimens with white and brown speckling.

Description of material examined

Radiolar crown with basal lobes semi-circular. Basal membrane absent. 12–22 pairs of radioles, supported by 8–10 vacuolated cells in cross section near base ( Figure 7 View Figure 7 ). Radiolar flanges and eyes absent. No observed pinnular appendages on dorsal lip. Posterior peristomial ring reaching almost to base of radioles ( Figure 8 View Figure 8 (a)). Ventral sacs absent. Ventral lappet separated by parallel ventral lamellae ( Figure 8 View Figure 8 (b,c)). Subdermal peristomial eyes present. Ventral shields conspicuous. First shield wider with M-shaped anterior edge, subsequent shields uniformly sized, in contact with neuropodial tori ( Figure 8 View Figure 8 (c)). Superior and inferior collar chaetae elongate and narrowly hooded ( Figure 8 View Figure 8 (d)). Superior thoracic chaetae elongate and narrowly hooded. Inferior thoracic chaetae shorter, broadly hooded, hoods twice the width of shaft, and 5–7 times as long as maximum width ( Figures 8 View Figure 8 (e) and 9(a,c)), type B ( Capa and Murray 2015a). Thoracic neuropodial uncini avicular ( Figure 9 View Figure 9 (b)) with several rows of uniformly sized teeth above main fang, occupying half length of main fang ( Figure 8 View Figure 8 (f,g)); neck shorter than breast, handle 1–1.5 times distance from main fang to breast ( Figure 9 View Figure 9 (d)). Thoracic neuropodial companion chaetae enlarged subdistally, covered with several rows of uniformly sized teeth, ending in a thin laterally compressed mucro ( Figure 8 View Figure 8 (g,h)). Anterior and posterior abdominal chaetae narrowly hooded ( Figure 4 View Figure 4 (i)). Abdominal uncini avicular with several rows of uniformly sized teeth above main fang, occupying half length of main fang ( Figure 8 View Figure 8 (j)).

Remarks

Examination of morphological characters uncovered unique features in the shape and proportion of ventral shields and thoracic uncini, and the number of vacuolated radiolar support cells ( Table 2). This species most closely resembles P. aulaconota   , described from Japanese waters, and concurs with the original ( von Marenzeller 1884) and subsequent descriptions ( Johansson 1927; Okuda 1939), and with a preserved P. aulaconota   specimen from Japan (AM W.37073). However, we were unable to examine the type specimen of P. aulaconota   . It also agrees well with the description of P. cf. aulaconota   of Capa and Murray (2015a).

However, phylogenetic analyses, regardless of the marker used, recovered sequences from South Australian specimens nested within the Parasabella sp. 1   clade ( Figure 2 View Figure 2 (a,b)) and separated by small genetic distance if compared with other congeners ( Tables 5 and 6), which provides strong evidence of the identity of the specimens. The two specimens (AM W.32563 and AM W.37041) from Florida and Sydney Harbour, Australia, identified as Parasabella sp. 1   by Capa and Murray (2015a), were not included in their taxonomic descriptions of that paper as they were very small and had ‘indeterminate morphology’ ( Capa and Murray 2015a, p. 773).

Overall, these results also imply that molecular taxonomy may help classify morphologically complex groups where intraspecific and interspecific variation often overlap.

Distribution USA (Florida), Australia (New South Wales, South Australia).

AM

Australian Museum