AMBLYRHYNCHUS CRISTATUS, 2017

AMBLYRHYNCHUS CRISTATUS

JEFFREYSI SUBSP. NOV.

( FIGS 6O–U, 7, 9A)

LSID urn:lsid:zoobank.org:act:CFCD0F52-D88B-4DC6-A0D6-3C1D9B766476

Holotype: CAS 12690 About CAS , coll. by J. R. Slevin in 1906, Isla Wolf , no exact locality.

Paratypes (N = 7): CAS 12686–12689 About CAS , 12691–12693 About CAS , same data as holotype ; CAS-SUR 4777 , coll. by E. Heller and R. E. Snodgrass in 1905, Isla Wolf , no exact locality .

Specimens examined (N = 14): Wolf : CAS 12686–12693 CAS-SUR 4777, coll. by E. Heller and R.E. Snodgrass in 1905, no exact locality. Darwin: CAS 12693–12696, 12698, coll. In 1906 by J.R. Slevin, Isla Darwin, no exact locality.

Etymology: The subspecies name is a patronym for Jeffreys Málaga, a ranger of the Galápagos National Park with an outstanding interest and enthusiasm for the fauna and flora of the Galápagos, and especially for marine iguanas. Jeffreys Málaga has been awarded several times ‘Guardaparque del Año,’ or Park Warden of the Year and has been an essential part of our team during several excursions to the Galápagos.

Geographic distribution: Wolf, Darwin (tentative assignment), Roca Redonda and very likely their satellite islets ( Fig. 8).

Diagnostic description: Amblyrhynchus cristatus jeffreysi subsp. nov. is the smallest subspecies of marine iguana (mean SVL 191 mm, up to a maximum of 245 mm). Mature males have a poorly developed crest of spines and weakly conical supracephalic scales. In preservative, males are almost uniformly dark brown or blackish dorsally, with few small ochre dots, and a contrasting lighter crest, mostly ochre. More specifically, this subspecies also has a high number of scale rows at midbody (144.3 ± 8.7), a high number of lamellae under the third (29.0 ± 1.5) and fourth (33.2 ± 2.9) toes and a very high number of scales along the dorsal (125.1 ± 9.9) and caudal crest (146.1 ± 9.7) (see also Figs 4, 6O–U, 9A, Table 1).

Description of the holotype: CAS 12690 ( Figs 6O, 9A), adult female preserved in 70% ethanol, in relatively good condition despite long incisions (likely realized during the fixation process) running along the ventral side of the body, limbs and tail, and the posterior half of the body being slightly discoloured. SVL (208 mm) shorter than tail length (332 mm). Head 36.9 mm long (HL1), 30.2 mm high and 31.5 mm wide. Fourth toe length 38.2/ 39.4 mm. Rostral scale in contact with three adjacent supra-supralabials. Anteriormost supralabials in contact below the mental. Nine supralabials on both sides; 12 infralabials on the right side, 11 on the left side. Internasal and rostal scales separated by a row of at least four flat and rounded relatively small scales. Four relatively large and weakly convex frontonasal scales, asymmetrically arranged, posterior to and in contact with the internasal. Subdigital lamellae 29/29 under the third toe, 33/32 under the fourth toe; 275 tranversal row of minute scales at midbody. Dorsal crest weakly developed, 16 spiny scales running along the dorsal side of the neck (Cnc), followed by a well-differentiated postnuchal gap of 11 very reduced scales (Cng), 89 spiny scales running along the dorsal side of the trunk (Cdc), remarkably reduced in the posterior half of the body, then 161 scales on the dorsal side of the tail.

After 110 years of preservation in ethanol, original colour pattern still clearly visible, although the posterior half part of the body tends to be lighter, apparently because of the removal of the superficial layer of epidermis. Background coloration of the dorsal and lateral sides of the whole body dark brown. Trunk, lateral sides of the neck and of the base of the tail moderately maculated by tiny ochre spots, whose density increase at the interface of lateral and ventral sides. Dorsal and lateral sides of the head dark to chocolate brown, the larger conical scales covering the top of the head slightly lighter. Crest spines on the nuchal and dorsal segments light ochre, remarkably contrasting with the dark background coloration, whereas spines on the caudal segment almost as dark as the rest of the tail. Dorsal and lateral sides of the tail uniformly dark brown, with exception of few very light ochre spot on the lateral side of the base of the tail. Dorsal and lateral sides of the limbs brownish, immaculate. Mental region, ventrum, ventral sides of the limbs and of the tail uniformly light ochre, with exception of a gular collar that is distinctly darker.