Dentiraja polyommata (Ogilby 1910), 2008

Rigby, Cassandra L., White, William T. & Kyne, Peter M., 2017, Description of the egg cases of Dentiraja polyommata (Rajiformes: Rajidae) and Asymbolus pallidus (Carcharhiniformes: Scyliorhinidae) from Queensland, Australia, Zootaxa 4294 (3), pp. 329-341 : 331-333

Dentiraja polyommata (Ogilby 1910)

Description. The egg case of D. polyommata is small (47.3–60.6 mm ECL) and rectangular in shape ( Table 1: Fig. 2 ). It is convex on both sides with the surface covered in dense, fine, golden longitudinal fibres. Underneath these fibres, the surface of the egg case appears smooth and glossy but has fine, shallow and straight longitudinal striations and is golden-tan in colour when fresh, darkening slightly after freezing ( Fig. 2 ) and after being fixed in 10% formalin and stored in 70% ethanol. Both anterior and posterior aprons are broad and well developed with the posterior apron considerably longer than the anterior one. The posterior horns are longer than the anterior horns, with both sets of horns tapered and curved inwards. The lateral keels are well defined and very narrow (<5% of PCW). All measurements are provided in Table 1.

Measure D. polyommata (n = 16) D. endeavouri (n = 4) Remarks. Dentiraja polyommata is a small skate (attaining 380 mm total length, TL) endemic to eastern Australia in a narrow range from off Townsville to Rockhampton (~19.0867– 23.2375°S; 148.3851– 153.7681°E) at depths of 135–320 m ( Last & Stevens 2009). There has been historical confusion with a similar eastern Australian species, D. endeavouri which was only recognised as a separate species recently, based on differences in colour and some subtle morphometric characters ( Last 2008). This is the first confirmed record and description of the egg cases of D. polyommata (noting that Kyne et al. (2008) provided descriptions of the egg cases of D. endeavouri , but published using the name D. polyommata ).

Material examined: Retained: CSIRO H 8062-01, two egg cases 53.3 and 51.2 mm ECL (from 325 mm TL female), Swain Reefs 21.8505° S, 152.9720° E, 196 m depth, 16 Jun 2011; CSIRO H 7446-06, two egg cases 52.4 and 55.3 mm ECL (from 329 mm TL female), Swain Reefs 22.1468° S, 153.0703° E, 154 m depth, 22 Mar 2012; CSIRO H 8063-01, two egg cases 51.6 and 52.8 mm ECL (from 312 mm TL female), Swain Reefs 22.1436° S, 153.0700° E, 148 m depth, 23 Mar 2012; CSIRO H 8064-01, two egg cases 55.1 and 54.4 mm ECL (from 326 mm TL female), Swain Reefs 23.5830° S, 152.3471°E, 230 m depth, 11 Oct 2010. Not retained: field code SB0206#2.2, one egg case 47.3 mm ECL (from 319 mm TL female), Swain Reefs 23.6683° S, 152.3395° E, 207 m depth, 2 Jun 2011; field code SM0204#61.4, two egg cases 57.1 and 56.2 mm ECL (from 340 mm TL female), Swain Reefs 22.2489° S, 153.0701° E, 150 m depth, 2 Apr 2012; field code SM0504#71.2, two egg cases 53.1 and 55.3 mm ECL (from 341 mm TL female), Swain Reefs 22.2501° S, 153.0704° E, 152 m depth, 5 Apr 2012; field code SM1604#105.101, two egg cases 58.2 and 60.6 mm ECL (from 366 mm TL female), Swain Reefs 23.2412° S, 152.2471° E, 242 m depth, 16 Apr 2012; field code SM1704#106.39, one egg case 60.1 mm ECL (from 354 mm TL female), Swain Reefs 23.5758° S, 152.3397° E, 242 m depth, 17 Apr 2012.

Figures

FIGURE 2. Egg case of Dentiraja polyommata in dorsal (upper image) and lateral (lower image) views (CSIRO H 8062 - 01). Scale bar = 10 mm.