Himantura uarnak ( Gmelin, 1789 )

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, Zootaxa 4951 (3), pp. 511-528 : 520-521

Himantura uarnak ( Gmelin, 1789)

Darkspotted whipray, Coach whipray

Fig. 8

oaja uarnak Gmelin, 1789: 1509 ; no types known; type locality: Red Sea.

Material examined: No specimen collected, underwater photograph, Socotra Island, Di Hamri, 5 m depth, 24 April 2018 .

Distinctive characters: eẚmanṫura uarnak is characterised by having a rhomboidal disc in adults; eyes small, protruding; tail very slender and very long, whip-like, subcircular in cross-section, without cutaneous folds, length of tail ~3–3.5 times disc width; and only 1-3 slightly enlarged, flattened, heart-shaped thorns middorsally; nasal curtain broad and short with finely fringed posterior margin (Last eṫ al. 2016c).

Colouraṫẚon: Dorsal surface of disc light yellowish brown, whitish or greyish with numerous, round to oblong, small dark brown to black spots smaller than eye diameter, sometimes spots irregular, forming vermiculate pattern; tail densely dark spotted above anterior to sting, weakly banded posteriorly. Ventral surface almost entirely white (Last eṫ al. 2016c).

Distribution: Ranges from the Red Sea and eastern Mediterranean Sea southward to South Africa (Eastern Cape Province) and islands of the Western Indian Ocean, eastward to southern India. Records from the Western Pacific Ocean require an additional study. In the Arabian region, the species is known from the Red Sea ( Golani & Bogorodsky 2010), Gulf of Tadjoura (Lips eṫ al. 2016), Oman (Randall 1995) and Pakistan (Psomadakis eṫ al. 2015). The record from the Gulf by Almojil eṫ al. (2015) is based on a misidentification of eK leoparda Manjaji- Matsumoto & Last, 2008. Jabado eṫ al. (2018) observed both species in the Gulf in coastal waters of the United Arab Emirates using baited remote underwater video and noted eK uarnak as more frequently recorded than eK leoparda, yet reproduced a photograph of the latter only. Golzarianpour eṫ al. (2020) collected 389 specimens of six species, including eK leoparda, for their study but no eK uarnak was recorded in the Gulf or Gulf of Oman. Both species, however, are known from off Oman based on genetic data (Henderson eṫ al. 2015). Pending conclusive evidence, the presence of eK uarnak in the Gulf presently remains unconfirmed.

Remarks: The photographed individual is a female of about one meter disc width, which matches well all characters of eẚmanṫura uarnak given by Last eṫ al. (2016c). It can be identified particularly based on the colour pattern as described above. The species occurs on sand and mud bottom of lagoons and seaward reefs, at depths of 0–50 m ( Weigmann 2016). The present confirmed record is based on a single individual, which was observed on sand bottom mixed with small stones in a coral-reef area at Di Hamri, north-eastern part of Socotra Island, at a depth of 5 m. A recently described species from off Tanzania, eẚmanṫura ṫuṫul Borsa eṫ al., 2013 is a junior synonym (Last eṫ al. 2016c; Weigmann 2016, 2017), as confirmed by a phylogenetic analysis, in which southern Red Sea specimens of eK uarnak, Tanzanian specimens described by Borsa eṫ al. (2013) as eK ṫuṫul and specimens from southern India identified by Kumar eṫ al. (2020) as eK ṫuṫul form one genetic lineage (unpublished data). eẚmanṫura uarnak is included as vulnerable in IUCN Red List Assessments and urgently requires conservation management (Manjaji- Matsumoto eṫ al. 2016a).

The similar eẚmanṫura leoparda, which is widespread in the Indo-West Pacific, including the Gulf and Lessepsian records from off Lebanon and Turkey, can easily be confused with eK uarnak. It might be found in the Red Sea and off Socotra Archipelago, too, but differs by having a middorsal row of a dozen small denticles followed by two prominent heart-shaped thorns and relatively large dark brown spots or rings on disc that are as large as or larger than eye diameter ( Manjaji-Matsumoto & Last 2008; Last eṫ al. 2016c).

Figures

FIGURE 8. eẚmanṫura uarnak, underwater photograph, Di Hamri, Socotra Island, 5 m depth. Photo by S.V. Bogorodsky.