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Chioninia coctei

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Taxonomy [top]

Kingdom Phylum Class Order Family
ANIMALIA CHORDATA REPTILIA SQUAMATA SCINCIDAE

Scientific Name: Chioninia coctei
Species Authority: (Duméril & Bibron, 1839)
Common Name(s):
English Cape Verde Giant Skink, Bibron’s Skink, Cocteau's Lizard
Synonym(s):
Charactodon coctei (Duméril & Bibron, 1839)
Euprepes coctei Duméril & Bibron, 1839
Gongylus coctei (Duméril & Bibron, 1839)
Macroscincus coctaei (Duméril & Bibron, 1839) [orth. error]
Macroscincus coctei (Duméril & Bibron, 1839)

Assessment Information [top]

Red List Category & Criteria: Extinct ver 3.1
Year Published: 2013
Date Assessed: 2012-09-17
Assessor(s): Vasconcelos, R.
Reviewer(s): Bowles, P.
Justification:
Listed as Extinct on the basis that this species has not been found in recent surveys of the only Cape Verde islands where it was known to survive (it was last seen alive in 1912).

Geographic Range [top]

Range Description: This species was endemic to the Cape Verde islands, where it had been recorded from the islets Branco and Raso (Schleich 1987, Bocage 1873). These islands have a combined area less than 10.7 km2. Its area of occupancy would have been an estimated 7 km2 (Vasconcelos et al. 2013). It appears to have historically been more widespread on the islands (Bocage 1873), with subfossils reported from São Vicente and Santa Luzia (Mateo et al. 1997). It may also have occurred on São Nicolau, based on the reports of local fishermen, but evidence for this is lacking (Miralles et al. 2011). Mateo et al. (2005) reported finding partial remains of a juvenile in cat faeces on Santa Luzia, but a five-day survey of this island in 2006 failed to record the species (Miralles et al. 2011, Vasconcelos et al. 2013). Additional subfossil remains have been found near a beach on this island (R. Vasconcelos pers. comm. 2012).
Countries:
Native:
Cape Verde
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: This species was last seen alive in 1912, and has been considered extinct by some authors (e.g. Andreone and Guarino 2003) and in the First Red List of Cape Verde (Schleich 1996). A recent five-day survey of Santa Luzia failed to recover evidence of a surviving population (Miralles et al. 2011, Vasconcelos et al. 2013), and these authors likewise concluded that this skink is now extinct. The most recent record of this species was a mandible of a juvenile collected from cat faeces on Santa Luzia in 2005, since when the cat population has increased and the invasive animals are now widespread on the island (R. Vasconcelos pers. obs.). Repeated surveys of Branco and Raso since this species was last recorded have also failed to rediscover it.

Habitat and Ecology [top]

Habitat and Ecology: This species inhabited rocky clefts within seabird colonies (shearwaters and petrels), where skinks lived communally. This was a crepuscular and partially nocturnal lizard (Vaillant 1882), which preyed on bird eggs and fledglings (Hazevoet 1994). Animals would also scavenge dead birds (Hazevoet 1994). Females laid two eggs per clutch (Andreone and Guarino 2003). It is hypothesized that sexual maturity was reached at five (males) or six (females) years of age (Andreone and Guarino 2003), but age estimation in these lizards is uncertain and maturity may have been reached later. Sexual dimorphism was most pronounced after eight years.
Systems: Terrestrial

Use and Trade [top]

Use and Trade: Use of this species has been reported for local subsistence hunting, for medicine (as a traditional painkiller - Bocage 1873), and for the international pet trade. It was also harvested for its skin, which was used to make shoes (Bocage 1873).

Threats [top]

Major Threat(s): Rats, cats and dogs have all been introduced to Santa Luzia, where they represented the major predators of this lizard (Andreone and Guarino 2003). As well as directly preying on the skink, rats and cats competed with them for food and may have caused declines in the seabird colonies on which this lizard relies. Particularly in times of drought, humans have also used the skink as a food source (Schleich 1982), for medicine and skins (Bocage 1873), and commercial trade for scientific purposes (Andreone and Guarino 2003). Low population numbers and recruitment, slow growth rates (Andreone and Guarino 2003), and a restricted range on a single island and two smaller islets all put this skink at extremely high risk from these threatening processes, as well as from stochastic events (particularly droughts, thought likely to have contributed to the species' extinction - Andreone 2000), and it is now thought to be extinct.

Conservation Actions [top]

Conservation Actions: No conservation measures are applicable for this skink, which has not been found in recent exhaustive surveys of its known sites and is presumed to be extinct. Conservation awareness programs could benefit by highlighting the fate of this large lizard and the need to prevent future extinctions of island endemics.

Citation: Vasconcelos, R. 2013. Chioninia coctei. The IUCN Red List of Threatened Species. Version 2014.2. <www.iucnredlist.org>. Downloaded on 30 September 2014.
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