Branchiomma sp. B

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: 2659-2661

publication ID

http://doi.org/ 10.1080/00222933.2020.1862334

persistent identifier

http://treatment.plazi.org/id/03C3F130-FF7A-F42A-0B8B-DD9B0E26333F

treatment provided by

Marcus

scientific name

Branchiomma sp. B
status

 

Branchiomma sp. B   Capa et al. 2013

( Figures 3–5 View Figure 3 View Figure 4 View Figure 5 ; Tables 3 and 4)

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   .49876, AM W.49877, AM W.49867.001 (on SEM pin), AM W.49878, AM W.49879, AM W.49868.001 ( SEM pin), AM W.49869.001 ( SEM pin).

Comparative material examined

Branchiomma sp. B   , AM W. 31816 (1), AM W. 35563, Fort Pierce , Florida, USA, 27° 22 ʹ 51”N, 80°15 ʹ 54”W, 2006; AM W GoogleMaps   .35574 (1), AM W. 35575 (1), Oahu , Hawaii, USA, 21° 25 ʹ 48”N, 157°57 ʹ 43”W, 2008; AM W GoogleMaps   . 35632 (1), North Invasion Beach , Saipan, Japan, 15° 7 ʹ 47”N, 145°41 ʹ 32”E, 2009; AM W GoogleMaps   .35568 (1), AM W.35569 (1), AM W.35570 (1), AM W.35571 (1), AM W. 35572 (1), AM W.36444 (1), Darwin , NT, 12°30’S, 130°48 ʹ E, 2005 GoogleMaps   .

Branchiomma bairdi, AM W.   35564 (1), AM W.31822 (1), Fort Pierce , Florida, USA, 27° 26 ʹ N, 80°19 ʹ W, 2006 GoogleMaps   .

Size and colour pattern

Specimens measured 13–39.5 mm in body length (thorax and abdomen) and 1.5–3 mm in width, with 5–8 thoracic and numerous abdominal chaetigers. Live specimen body colour brown to greenish-brown, some with small dark brown spots on the thorax and abdomen ( Figure 3 View Figure 3 (a)). Radioles greenish with white and brown bands that continue along the radiolar stem, pinnules and stylodes ( Figure 3 View Figure 3 (b)). White macrostylodes. Light red radiolar eyes.

Description of material examined

Radiolar crown with basal lobes semi-circular. Basal membrane absent. 12–18 pairs of radioles. Radiolar flanges absent. Paired stylodes present, digitiform or strap-like, slightly shorter than length of corresponding pinnules. Macrostylodes present on some specimens, strap-like,twice as long as neighbouring pairs ( Figure 4 View Figure 4 (g)). Unpaired basal stylodes present, digitiform, slightly shorter than length of basal pinnules ( Figure 4 View Figure 4 (e)). 19–20 pairs of radiolar eyes present, light red, along the entire lateral margins of radioles alternating with stylodes. Eyes are small, covering less than half the width of radiolar rachis at mid-radiolar length ( Figure 3 View Figure 3 ). Dorsal lips with long radiolar appendages, equal to 1/3 of the crown in length ( Figure 4 View Figure 4 (a,f)). Ventral sacs outside branchial crown. Dorsal margins of peristomial ring collar widely separated, not fused to faecal groove; ventral lappets separated by a midventral incision ( Figure 4 View Figure 4 (a)). Subdermal peristomial eyespots present. Interramal eyespots present in thorax and abdominal chaetigers. Ventral shields conspicuous and in contact with neuropodial tori ( Figure 4 View Figure 4 (d)). First shield larger with a semi-circular anterior margin ( Figure 4 View Figure 4 (c)). Superior and inferior collar chaetae elongate and narrowly hooded. Superior thoracic chaetae elongate and narrowly hooded, inferior thoracic chaetae spine-like ( Figure 4 View Figure 4 (h)). Thoracic neuropodial uncini avicular ( Figure 5 View Figure 5 (a,b)), with 2–3 rows of teeth over main fang, occupying half length of main fang ( Figure 4 View Figure 4 (i,j)); neck short, <0.6 times distance of tip of main fang to breast. Abdominal neuropodial uncini similar to thoracic uncini ( Figure 4 View Figure 4 (k)).

Remarks

The examined specimens from South Australia show morphological features shared with Branchiomma sp. B   . (e.g. the length of the neck vs the distance between the main bang and breast – thoracic uncini E/G – or colour of radiolar eyes); but there is also some resemblance of these specimens to Australian specimens identified as Branchiomma bairdi   by Capa et al. (2013) ( Table 1). And there are even some features that seem to be unique for these specimens (e.g. colour pattern, length of dorsal lips, Table 1).

Phylogenetic and pairwise genetic distances of the ITS region show the South Australian sequences belong to the same lineage and show little divergence from those referred to as Branchiomma sp. B   by Capa et al. (2013) ( Table 4). Consequently, we determine that they should be all considered members of the same species and suggest that the species has a broader morphological variation than was previously reported ( Capa et al. 2013). This species could be undescribed, but a recent morphological study by Keppel et al. (2018) suggested that specimens of Capa et al. (2013) from Hawaii could in fact be the true B. bairdi   . A broader comprehensive study incorporating both morphological and molecular data from worldwide localities and several morphotypes (ideally including well-identified adult specimens with conspicuous morphological features, and material from type localities) is needed to resolve the species name of the currently identified Branchiomma sp. B   .

Distribution

USA (Florida, Hawaii), Northern Mariana Island (Saipan), Australia (Northern Territory, South Australia)   .

AM

Australian Museum