Asaccus caudivolVulnerablelus | UAE National Red List of Herpetofauna: Amphibians & Terrestrial Reptiles, Sea Snakes & Marine Turtles
Location
Countries in Assessment
United Arab Emirates (the)
Does the assessment cover a marine EEZ area(s)?
Off
Scope (Assessment)
National
Taxon
Taxonomic Group
Vertebrates
Taxonomic Group Level 2
Reptiles
Assessed taxon level
Species
Taxonomic Notes
A recent systematic revision by Carranza et al. (2016), using an integrative approach including molecular (mitochondrial and nuclear markers) and morphological data, indicated that the species originally classified as Asaccus caudivolVulnerablelus (Arnold and Gardner 1994, Gardner 2013) was an assemblage of three different species that started diversifying during the Mid-Miocene. The analyses uncovered a very old diversification event that resulted in a case of microendemicity, where three morphologically and ecologically similar medium-sized species previously classified within A. caudivolVulnerablelus coexist in a very short and narrow mountain stretch.As a result of this study, two new species - A. gardneri and A. margaritae - were described, both of them widely distributed across the northern tip of the Hajar Mountains. Conversely the third species - Asaccus caudivolVulnerablelus sensu stricto - appears to be restricted to a small coastal area of the United Arab Emirates under heavy development, where the only two localities in which the species has ever been recorded occur. The molecular analyses indicate that A. caudivolVulnerablelus has been evolving independently from its sister taxon, A. gardneri, for approximately four million years.
Taxon distribution as listed in assessment
This species is only known from two localities along a narrow strip of the east coast of the United Arab Emirates: the type locality at Jebel Ra's, 2.5 km south of Khor Fakkan, Emirates of Sharjah; and a second locality (named ""locality 29"" by Carranza et al. 2016) a few kilometres further north of Sharm, Emirates of Fujairah. No specimens have been recorded from the type locality since 1973, and it is considered likely to have been extirpated from this locality (see Threats). Consequently, the only confirmed specimens that have been found in the past 45 years are restricted to the second locality. It is possible that the species occurs in other putatively suitable areas of the same coastal stretch that have not been surveyed as a result of restricted access due to development. The species has been found between sea level up to 20 m in elevation.
Habitats and Ecology
Ecological system type
Habitat
Habitat details as listed in assessment
The species is currently considered to be restricted to an isolated rocky outcrop along the Hajar Mountains on the eastern coast of the United Arab Emirates. It occurs from sea level up to 20 m in elevation and appears to prefer sea-facing rock cliffs with large boulders. It is strictly nocturnal: all specimens have been seen during the night and avoided surveyors' torch beams, retreating into crevices and holes or fleeing across boulders. Females breed year-round, laying a single egg multiple times a year.
Is there a map available in assessment?
Yes
Assessed status
Asessment status in full
Critically endangered
Assessment status abreviation
CR
Assessment status criteria
B1ab(iii,v)+2ab(iii,v)
Assessment rationale/justification
This species is the only reptile currently known to be endemic to the United Arab Emirates. It is only known from two localities along a narrow strip of the east coast of the United Arab Emirates. No specimens have been recorded from the type locality (near Khor Fakkan, Emirates of Sharjah) since 1973, with the only recent records being from a second known locality, a few kilometres further north of Sharm, Emirates of Fujairah. The only confirmed specimens that have been found in the past 45 years are therefore restricted to the second locality and the species is consequently considered to survive at a single location defined by the threat from development. It is possible that the species occurs in other potentially suitable habitats along the same coastal stretch, or persists at the type locality, and additional survey in these areas is urgently required. The species has been found between sea level up to 20 m in elevation. Both the extent of occurrence (EOO) and the area of occupancy (AOO) are estimated at 8 km<sup>2</sup> based on a 2x2 km grid drawn around the two localities, however both the EOO and the AOO are in reality very much more restricted, with the species found on isolated rocky outcrops and presumed to have been lost from one of these.The species is listed as Critically Endangered (CR B1ab(iii,v)+2ab(iii,v)) as a result of its restricted EOO and AOO, with both of the known localities, as well as areas along the east coast of the United Arab Emirates with apparently similar habitat characteristics, under heavy transformation or have already been converted for industrial, residential or tourist development. The species is currently considered to persist at a single location defined by the described threats, which are resulting in a continuing decline in the extent and quality of this species' habitat, and inferred to be causing a continuing decline in the number of mature individuals.Conservation actions are urgently required for this species, including ex situ conservation, and the potential for the establishment of new sub-populations should be investigated.
About the assessment
Assessors/contributors/reviewers listed
UAE National Red List Workshop
Affliation of assessor(s)/contributors/reviewers listed on assessment
Assessor affiliation specific
Government|IGO
Criteria system
Criteria system specifics
IUCN v3.1 + Regional Guidelines v4.0
Criteria system used
IUCN
Criteria Citation
IUCN. 2012. IUCN Red List Categories and Criteria: Version 3.1, Second edition. IUCN, Gland, Switzerland and Cambridge, UK. iv + 32pp pp. And IUCN. 2012. Guidelines for Application of IUCN Red List Criteria at Regional and National Levels: Version 4.0. Gland, Switzerland and Cambridge, UK: IUCN. iii + 41pp.
Endemism
Endemic to region
Not assigned
Endemism Notes
Is an endemic?: Not_assigned
Conservation
Threats listed in assessment
The only locality where an extant population has been confirmed is under severe transformation (Carranza et al. 2016 shows an image of the locality with construction machinery in the foreground) and is zoned for development and road construction. The site is subject to dynamite blasting as part of the construction and is already under heavy transformation. This may be one of the only areas retaining suitable habitat for this species.The type locality, a mountain outcrop, is surrounded by quarrying, industrial development and harbour (importation port) which destroyed most of the suitable habitat for the species. Access to the area due to the harbour and quarrying activities is now restricted, which prevents surveys at the type locality.Marine pollution, primarily oil pollution, is an additional likely threat, with significant numbers of oil spoils known in the area.
Conservation Measures
Conservation measures:
