AMBLYRHYNCHUS CRISTATUS, 2017

AMBLYRHYNCHUS CRISTATUS

HAYAMPI SUBSP. NOV.

( FIGS 6K–N, 7, 9B)

LSID urn:lsid:zoobank.org:act:A5D505A8-63E7-48F8-BCB9-1EFC68ED1FE2

Holotype: CAS 12471 About CAS , coll. by J. R. Slevin and E.S. King in 1906, NW coast of Isla Marchena .

Paratypes (N = 11): CAS 12449 About CAS , 12451 About CAS , 12452 About CAS , 12456 About CAS , 12458 About CAS , 12460 About CAS , 12464 About CAS , 12467 About CAS , 12469 About CAS 12473, 12474, same data as holotype .

Specimens examined (N = 12): Marchena : CAS 12449, 12451, 12452, 12456, 12458, 12460, 12464, 12467, 12469, 12471, 12473, 12474, coll. by J.R. Slevin and E.S. King in 1906, NW coast of the island.

Etymology: The subspecific epithet hayampi refers to the word used to designate the common iguana in Kichwa (a Quechuan language representing one of the three official languages of Ecuador and currently spoken by a million people in South America).

Geographic distribution: Marchena and very likely its satellite islets ( Fig. 8).

Diagnostic description: Amblyrhynchus cristatus hayampi subsp. nov. is a medium- to large-sized subspecies of marine iguana (mean SVL 299 mm, up to a maximum of 379 mm). Mature males have a well-developed crest of spines and relatively pronounced conical supracephalic scales. In preservative, males are dark grey or blackish dorsally, marbled or speckled with small ochre dots that frequently align and merge to each other to form transversal stripes along the body. This subspecies also has a very low number of lamellae under fourth (26.5 ± 2.2) toes, contrasting with a rather medium number of lamellae under the third toes (25.5 ± 1.8) and a very low number of scales along the caudal crest (130.5 ± 6.0) (see also Figs 4, 6K–N, 9B, Table 1).

Description of the holotype: CAS 12471 ( Figs 6N, 9B), adult male preserved in 70% ethanol, in relatively good condition, with exception of long incisions (likely realized during the fixation process) running along the ventral side of the body, limbs, digits and tail, and the removal of the superficial layer of the epidermis in several distinct places. Hemipenes inverted and therefore not visible. SVL (295 mm) shorter than tail length (369 mm). Head 48.5 mm long (HL1), 35.2 mm high and 42.5 mm wide. Fourth toe length 46.3/ 44.9 mm. Rostral scale in contact with two adjacent supra-supralabials. Anteriormost supralabials in contact below the mental. Nine supralabials on both sides, ten infralabials on both sides. Internasal and rostal scales separated by a row of at least four small granular scales. Three frontonasal scales, posterior to and in contact with the internasal, the two exteriormost being larger and more conical than the smaller and relatively flat medium one. Subdigital lamellae 29/29 under the third toe, 23/22 under the fourth toe. Femoral pores indistinct (not counted); 271 tranversal rows of minute scales at midbody. Dorsal crest moderately developed, 15 spiny scales running along the dorsal side of the neck (Cnc), followed by a well-differentiated postnuchal gap of 11 very reduced scales (Cng), 91 spiny scales running along the dorsal side of the trunk (Cdc), then 138 scales on the dorsal side of the tail.

After 110 years of preservation in ethanol, original colour pattern still visible. Background coloration of the dorsal and lateral sides of the body very dark brown, with lighter, chocolate brown rounded spots (ochre when superficial layer of skin removed) variable in size and forming complex reticulated patterns. Irregularly distributed across the back, their absence makes visible three or four (hardly distinguishable) transversal spindle-shaped areas of immaculate dark brown background. Anterior part (postnuchal region) and posterior part (pelvic region) of the dorsum region darker than the middle of the dorsum, as less densely maculated. Dorsal and lateral side of the head ochre to chocolate brown, with large conical scales covering the dorsal side of the head; these scales lighter due to the presence of concretions of undetermined origin at their base (likely deposited during the lifetime of the animal). Crest spines chocolate brown on the nuchal segment, mostly ochre on the trunk segment (with exception of few series of one to three consecutive dark brown spines corresponding with the darker spindle-shape spotless area of the dorsum), and dark brown on the caudal segment. Dorsal and lateral sides of the tail uniformly dark brown (with exception of large ochre patches where the superficial layer of the skin has been removed). Dorsal and lateral sides of the limbs brownish, their distal parts (forearm and manus for forelimbs, toes for hindlimbs) darker than the proximal ones. Mental region, ventrum, ventral sides of the limbs and of the tail uniformly light ochre, with exception of a thin gular collar and the ventral side of manus and pes which are distinctly darker.