Geochelone phantastica

(Van Denburgh, 1907)
Fernandina (Narborough) Island tortoise

This species is known from only a single old adult male collected in 1906 and should probably be considered extinct. It has an extremely saddle-shaped, gray-black carapace (86 cm) with a shallow cervical indentation, and the anterior and posterior marginal scutes strongly upturned. The carapace narrows anteriorly; height at the cervical indentation is more than 53% of the straight carapacial length. Vertebral 1 is longer than broad, the others are broader than long, and the 5th is expanded. Some radiations and growth annuli are visible on the vertebrals and pleurals. Eleven marginals lie on each side, and a single, undivided, upturned supracaudal scale is present. The 1st marginals are expanded and more upturned than in any other Galápagos species (their ventral sides are almost vertical). Lateral marginals are small, but the 8th is not reduced. The gray-black, well-developed plastron is shorter than the carapace with both lobes tapered; the hindlobe bears a slight posterior notch. The plastral formula is: abd > hum > fem > an > gul > pect; the paired gulars do not project beyond the anterior carapacial rim. The bridge is very narrow (approximately 35% of carapace length) with single short axillary and inguinal scutes. The head is of moderate size, with a nonprotruding snout and a weakly hooked upper jaw. Its prefrontal scale is small and divided longitudinally, followed by a single, somewhat larger frontal. The head is gray with a yellow lower jaw and throat. The gray neck is long with the 4th cervical vertebra biconvex; limbs and tail are also gray. Large scales cover the anterior surfaces of the forelimbs. The tail is short and lacks a large terminal scale.

Geochelone phantastica is known only from Fernandina (Narborough) Island of the Galápagos Islands.

The single specimen was collected on the side of a volcano in a rocky area with scattered grass clumps, cacti, bushes, and vines.

Natural History
All we know of the life style of this tortoise was reported by the collector, R. H. Beck (in Van Denburgh, 1914). When collected, on 3 April 1906 in the late afternoon, the tortoise was eating grass, and there was evidence that tortoises on the island had also been feeding on Jasminocereus cacti, which has rather strong spines. Beck also remarked that he found a rock along the trail that the male had apparently mounted in an attempt to copulate in the absence of females.

IUCN Red List Status (1996)
The entire Galápagos group (listed as Geochelone nigra) is considered Vulnerable (A2c, B1+2c); Geochelone phantastica itself is not included.
The status of this species is uncertain. Although it has not been seen since 1906, Hendrickson (1965) did find some old droppings and partially eaten Opuntia cacti, and a few individuals may still exist on some of the rather inaccessible parts of the island. MacFarland et al. (1974a) and Pritchard (1996a) pointed out that, regardless of its present status, its fate has been determined by natural causes (probably volcanism), since humans never exploited Fernandina Island, and no introduced mammals occur there.