|Scientific Name:||Raja pita Fricke & Al-Hassan, 1995|
Okamejei pita (Fricke & Al-Hassan, 1995)
|Taxonomic Source(s):||Weigmann, S., Stehmann, M.F.W. and Thiel, R. 2015. Okamejei ornata n. sp., a new deep-water skate (Elasmobranchii, Rajidae) from the northwestern Indian Ocean off Socotra Islands. Deep-Sea Research II 115: 18-29.|
The female holotype of the Pita Skate was comprehensively examined in a recent taxonomic assessment of Okamajei (Weigmann et al. 2015). This showed unequivocally that the Pita Skate does not belong to the genus Okamejei, but instead to either Leucoraja or Rajella. This is evidenced by its overall appearance, particularly the absence of dark-marked ventral pores (vs. dark marked ventral pores present in Okamejei), a rather short and thick tail (vs. a long and slender tail), a very short interdorsal space (vs. a wide interdorsal space), and a short postdorsal tail section (vs. a long postdorsal tail section). Due to the lack of an adult male specimen and the accordingly unknown clasper characters, the Pita Skate specimen cannot definitely be assigned to a genus and for the time being should be placed as incertae sedis in the general genus Raja Linnaeus. More specimens are urgently needed (Weigmann et al. 2015).
|Red List Category & Criteria:||Data Deficient ver 3.1|
|Assessor(s):||Moore, A. & Weigmann, S.|
|Reviewer(s):||Jabado, R. & Kyne, P.M.|
|Contributor(s):||Ishihara, H. & Stehmann, M.F.W.|
|Facilitator/Compiler(s):||Kyne, P.M., Jabado, R.|
The Pita Skate (Raja pita) was listed as Critically Endangered in 2008, based on the single known individual (the holotype) and the threats present at the location from which it was reported. However, re-evaluation of the available information in the 20+ years since its capture provides strong justification for a Data Deficient listing until further specimens that confirm its distribution are recorded. The rationale for this re-assessment is based on several factors:
|Previously published Red List assessments:|
|Range Description:||The Pita Skate (Raja pita) is endemic to the Arabian Seas region. Fricke and Al-Hassan (1995) reported the only known individual (the holotype), caught in the northernmost corner of the Arabian Gulf/Persian Gulf (hereafter referred to as the 'Gulf') at Fao, Iraq (29º54’N, 48º25’E).|
Weigmann et al. (2015), however, reviewed environmental information of the type locality and noted that this appears to be a wholly unsuitable environment for skates due to high turbidity, high sediment deposits from river outflow, and strong annual fluctuations of salinity and water temperatures (Al-Hassan and Hussain 1985). In the region of the estuary, water temperatures range from 15°C in winter to 35°C in summer and salinities range 14-28 ‰ during flood tide in autumn to 38-41 ‰ (Isaev and Mikhailova 2009). Furthermore, the whole Gulf is very shallow with an average water depth of about 35 m (Al-Hassan and Hussain 1985). Weigmann et al. (2015) summarised by noting that it is not surprising that except for the holotype of the Pita Skate, no rajid skates have ever been found in the Gulf.
The complete lack of confirmed (or even unconfirmed) records of this species at or near its reported type locality in the 20+ years since its reported collection appears to be highly unusual, especially given the increasing amount of elasmobranch survey effort in the Gulf, or general fish surveys that would have caught/recorded other demersal batoids and sharks. This has included fish surveys in Iraqi waters around the type locality (H. Ishihara, confidential unpublished data, 2015); gillnet and trawl surveys of elasmobranchs in Kuwaiti waters directly adjacent to the type locality (Bishop et al. 2016) and surveys of elasmobranchs landed in fish markets in Kuwait and the wider Gulf (Moore et al. 2012, Moore and Peirce 2013). A considerable number of additional fish surveys that also recorded demersal batoids and sharks (reviewed in Moore 2015) also did not record the Pita Skate. The lack of records for this species is even more conspicuous given that the species is highly distinctive (as the only rajid reported as occurring in shallow waters of the Arabian peninsula) and that it is illustrated in a widely-used FAO marine species identification guide for the region (Carpenter et al. 1997).
|FAO Marine Fishing Areas:|
Indian Ocean – western
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||There is no information available on the population of the Pita Skate, given that it is known only from the holotype of questionable origin. Recent elasmobranch surveys of fish markets and landing areas in neighbouring Kuwait (Moore et al. 2012), and trawl and gillnet surveys around Kuwait’s Boubiyan Island, within a few km of the type locality (Bishop et al. 2016) did not record any rajids, despite records of numerous other demersal batoids. This is supported by a large number of fish surveys in the Gulf that recorded demersal batoids and sharks but did not record rajids (reviewed in Moore 2015).|
|Current Population Trend:||Unknown|
|Habitat and Ecology:||The location from which the holotype (a 46 cm total length female) was reported is in the delta of the Tigris-Euphrates drainage, with high turbidity and extensive intertidal sand- and mud flats. The holotype was reported as being caught over a mud bottom in water not more than 15 m deep, around 3-4 km from the shore.|
|Continuing decline in area, extent and/or quality of habitat:||No|
|Use and Trade:||There is no information on possible use or trade of this species.|
|Major Threat(s):||While there are a number of threats to elasmobranchs in the northwestern Gulf (Moore 2011, Moore et al. 2012), further records of this species are required to confirm that it occurs in this location.|
There are no species-specific conservation measures in place. Further confirmed records, preferably backed by photographs and/or specimens with details of capture location etc., are urgently required, in particular adult males for generic assignment.
Al-Hassan, L.A.J. and Hussain, N.A. 1985. Hydrological parameters influencing the penetration of Arabian Gulf fishes into the Shatt Al-Arab River, Iraq. Cybium 9(1): 7-16.
Bishop, J.M., Moore, A.B.M., Alsaffar, A.H. and Abdul Ghaffar, A.R. 2016. The distribution, diversity and abundance of elasmobranchs in a modified subtropical estuarine system in Kuwait. Journal of Applied Ichthyology 32: 75-82.
Carpenter, K.E., Krupp, F., Jones, D.A. and Zajonz, U. 1997. Living marine resources of Kuwait, eastern Saudi Arabia, Bahrain, Qatar, and the United Arab Emirates. FAO, Rome, Italy.
Fricke, R. and Al-Hassan, L.A.J. 1995. Raja pita, a new species of skate from the Arabian/Persian Gulf (Elasmobranchii: Rajiformes). Stuttgarter Beiträge zur Naturkunde, Serie A (Biologie) 529: 1-8.
Isaev, V.A. and Mikhailova, M.V. 2009. The hydrography, evolution, and hydrological regime of the mouth area of the Shatt Al-Arab River. Water Resources 36(4): 380-395.
IUCN. 2017. The IUCN Red List of Threatened Species. Version 2017-2. Available at: www.iucnredlist.org. (Accessed: 14 September 2017).
Moore, A.B.M. 2011. Elasmobranchs of the Persian (Arabian) Gulf: ecology, human aspects and research priorities for their improved management. Reviews in Fish Biology and Fisheries 22: 35-61.
Moore, A.B.M. 2015. A review of sawfishes (Pristidae) in the Arabian region: diversity, distribution, and functional extinction of large and historically abundant marine vertebrates. Aquatic Conservation: Marine and Freshwater Ecosystems 25: 656-677.
Moore, A.B.M. and Peirce, R. 2013. Composition of elasmobranch landings in Bahrain. African Journal of Marine Science 35: 593-596.
Moore, A.B.M., McCarthy, I.D., Carvalho, G.R. and Peirce, R. 2012. Species, sex, size and male maturity composition of previously unreported elasmobranch landings in Kuwait, Qatar and Abu Dhabi Emirate. Journal of Fish Biology 80: 1619-1642.
Weigmann, S. 2016. Annotated checklist of the living sharks, batoids and chimaeras (Chondrichthyes) of the world, with a focus on biogeographical diversity. Journal of Fish Biology 88(3): 837-1037.
Weigmann, S., Stehmann, M.F.W. and Thiel, R. 2015. Okamejei ornata n. sp., a new deep-water skate (Elasmobranchii, Rajidae) from the northwestern Indian Ocean off Socotra Islands. Deep-Sea Research II 115: 18-29.
|Citation:||Moore, A. & Weigmann, S. 2017. Raja pita. The IUCN Red List of Threatened Species 2017: e.T161723A109916678.Downloaded on 13 December 2017.|