Rhynchobatus australiae Whitley 1939
Creators: name: Bogorodsky, Sergey V.
name: Zajonz, Uwe
name: Saeed, Fouad N.
name: Weigmann, Simon
Publisher: name: Zenodo
Year: 2021
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Elasmobranchii
Rajiformes
Rhinobatidae
Rhynchobatus
Rhynchobatus australiae

description: Rhynchobatus australiae Whitley, 1939
Bottlenose wedgefish
Figs. 5A & B, 6A
ohynchobaṫus djẚddensẚs ausṫralẚae Whitley, 1939: 245; holotype: AMS IA.4959; type locality: New South Wales, Australia.
Material examined: SMF uncatalogued [tissue sample SOC19-447], female, 73.5 cm TL, Socotra Island, fish market in Hadibo, 10 April 2019; SMF uncatalogued [tissue sample SOC19-448], male, 106.5 cm TL, Socotra Island, Ras Hawlaf, 11 April 2019.
Distinctive characters: ohynchobaṫus ausṫralẚae is characterised by having a long and pointed, bottle-shaped snout that is slightly constricted near tip; posterior tip of pectoral fins ending before pelvic fins; no prominent ridges on head and body; spiracle with two folds; upper caudal-fin lobe longer than the lower one (Weigmann 2011; Last eṫ al. 2016b; Jabado 2019).
Colouraṫẚon: Olivaceous to grey-brown dorsally; head without transverse black bands between eye and spiracles; side of body, posterior half of pectoral fins and sometimes distal third of pelvic fins with sparse coverage of small white spots, which do not extent posteriorly behind rear tip of first dorsal fin; black pectoral marking surrounded by a distinctive pattern of white spots (three or four spots around the marking plus one or two in front of it). Large individuals usually entirely dark, with white spots and pectoral marking hardly discernible (Last eṫ al. 2016b). Ventral surface almost uniformly white; underside of snout whitish in the middle, with violet hue laterally (Fig. 6A).
Distribution: Known from the Socotra Archipelago southward to Tanzania, eastward to eastern Australia, the Philippines and Papua New Guinea. The presence off Tanzania is confirmed by a specimen that nested within the same genetic lineage as oK ausṫralẚae (unpublished data). Last eṫ al. (2016b) included Mozambique in the distribution range of the species but the respective specimen from off Mozambique is referred to as oK djẚddensẚs by Giles eṫ al. (2016).
Remarks: Giles eṫ al. (2016) provided comprehensive data on the genetic structure and phenotypic variation within oK ausṫralẚae but no specimens from the Arabian region were examined in their study. Jabado eṫ al. (2017) summarized the conservation status of sharks, rays and chimaeras in the Arabian region and included three species of ohynchobaṫus: oK ausṫralẚae, oK djẚddensẚs (Forsskål, 1775) and oK laevẚs (Bloch & Schneider, 1801). Subsequently, Jabado (2018) listed those three species as present in the Gulf and Oman waters; whereby both publications lack evidence for the presence of oK ausṫralẚae in the region. So far, only one confirmed record of the species from the south-eastern part of the Arabian Sea existed based on two specimens landed at Cochin Fisheries Harbour, Kerala (Bineesh eṫ al. 2014). Jabado (2019) provided an illustrated guide for the identification of all known species of Rhinidae based on fresh specimens and fins. She noted the misidentification of species of the genus as a common problem for fisheries management and accurate identification as being critical for conservation programs.
ohynchobaṫus djẚddensẚs, described from the Red Sea, ranges southward to South Africa, northward to the Gulf and into the north-eastern part of the Arabian Sea (Last eṫ al. 2016b; Kizhakudan eṫ al. 2018), with positive records in the region from the Red Sea, south coast of Yemen (Bonfil & Abdallah 2004), Oman (Henderson eṫ alK 2015) and the Gulf (Almojil eṫ al. 2015; Henderson eṫ al. 2015). Kemp (1998) listed oK djẚddensẚs from the Socotra Archipelago, yet without sample or photographic evidence. Bonfil & Abdallah (2004) subsequently included a photograph taken from off Socotra Island in their FAO Guide (Ramon Bonfil, personal communication), confirming its occurrence there. ohynchobaṫus laevẚs is reported in the region from off Oman (Randall 1995 as oK djẚddensẚs; Henderson eṫ al. 2015), the Gulf (Almojil eṫ al. 2015; Henderson eṫ al. 2015), and Pakistan (Psomadakis eṫ al. 2015). Spaet & Berumen (2015) reported the presence of two species of ohynchobaṫus in the Red Sea, yet without providing photographs or descriptions. Until now, no evidence for the occurrence of oK ausṫralẚae in the Arabian region had been provided.
ohynchobaṫus djẚddensẚs differs from other species by having a large black, circular pectoral marking about as large as eye (may be indistinct or absent in adults), a dense pattern of white spots (sometimes also rings) on the dorsal surface, which do not or slightly extend forward of pectoral markings on mid-disc, absence of white spots on the pelvic fins, and prominent mask-like markings between the eyes (Last eṫ al. 2016b; Jabado 2019) (Fig. 5C). ohynchobaṫus laevẚs differs from its congeners by having a relatively broad snout, rows of small white spots on the dorsal surface of body and tail, spots beginning distinctly behind black pectoral markings (usually the dorsal surface anterior to first dorsal-fin origin remains unspotted), a pectoral marking that usually is a black ocellus with pale brown centre surrounded by 5–7 small white spots, and a blackish underside of snout (Last eṫ al. 2016b; Jabado 2019) (Figs. 5D & 6B).
Both examined specimens match well the descriptions of ohynchobaṫus ausṫralẚae provided by Weigmann (2011) and Last eṫ al. (2016b), representing the first confirmed record for the Arabian region. Elsewhere, the species typically lives on sedimentary substrata of shallow lagoons and coastal reef areas at depths of 0–60 m (Weigmann 2016). The female was taken from the fish market in Hadibo without precise collection data on locality and habitat, while the male was caught by two of the authors (SVB and FNS) in a large lagoon with silty sand bottom in an area mixed with small stones and sea weeds at a depth of 4–5 m in Ras Hawlaf bay, northern part of Socotra Island. The species is included as critically endangered in IUCN Red List Assessments and urgently requires conservation management (Kyne eṫ al. 2019b).
description: Published as part of Bogorodsky, Sergey V., Zajonz, Uwe, Saeed, Fouad N. & Weigmann, Simon, 2021, Notes on batoid fishes of the Socotra Archipelago (north-western Indian Ocean) with four new records, pp. 511-528 in Zootaxa 4951 (3) on pages 515-519, DOI: 10.11646/zootaxa.4951.3.5, http://zenodo.org/record/4668365