AMBLYRHYNCHUS CRISTATUS, 2017

AMBLYRHYNCHUS CRISTATUS

WIKELSKII SUBSP. NOV.

( FIGS 5D–F, 7, 9C)

LSID urn:lsid:zoobank.org:act:EBFA5A08-D5F9-41F9-BC2A-2FA65A707637

Holotype: SFM 57447, coll. by I. Eibl-Eibesfeldt in 1957, Crab-point, S of James Bay ( Isla Santiago ) (specimen originally designated as paratype of A. c. mertensi).

Paratypes: SFM 57446, 57448, 57449, same data as holotype (all of them originally designated as paratypes of A. c. mertensi).

Specimens examined (N = 13): Santiago : SFM 57446– 57449, coll. by I. Eibl-Eibesfeldt in 1957, Crab-point , S of James Bay (all of them being also paratypes of A. c. mertensi), SFM 57450, coll. by I. Eibl-Eibesfeldt in 1957, Crab-point, S of James Bay. CAS 12168 About CAS , 12169 About CAS , coll. by J.S. Hunter in 1906, no exact locality. Rábida: CAS 10613–10616 About CAS , CAS 11021 About CAS , coll. by E.S. King in 1905, no exact locality. SFM 25492, coll. during the Hassler expedition in 1872 .

Etymology: The subspecies name is a patronym for Prof. Dr. Martin Wikelski in recognition of his outstanding research on marine iguanas for several decades. Martin Wikelski has been fascinated by marine iguanas, which served as a study system for his behavioural and ecological research from his PhD onwards. He has published important papers on marine iguana ecology and conservation, for instance demonstrating the devastating effects of an oil spill on this species, and showing that marine iguanas can shrink in response to starvation induced by El Niño–based climate fluctuations.

Geographic distribution: Santiago, Rábida and very likely their satellite islets ( Fig. 8).

Diagnostic description: Amblyrhynchus cristatus wikelskii subsp. nov. is a medium-sized subspecies of marine iguana (mean SVL 236 mm, up to a maximum of 278 mm). Mature males have a moderately developed crest of spines and moderately conical supracephalic scales. In preservative, males have dark brown mottling on a yellowish to brownish slightly lighter dorsal background. This subspecies is also characterized by a very low number of scale rows at midbody (125.8 ± 7.7), a low number of lamellae under the third (24.9 ± 2.8) and fourth (29.0 ± 3.8) toes and a low number of scales along the caudal crest (135.9 ± 11.2) (see also Figs 4, 5D–F, 9C, Table 1).

Description of the holotype: SFM 57447 ( Figs 5D, 9C), adult male preserved in 70% ethanol, in a good condition with exception of a short ventral incision (likely realized during the fixation process). Hemipenes inverted and therefore not visible. SVL (257 mm) shorter than tail length (411 mm). Head 44.2 mm long (HL1), 35.1 mm high, and 40.5 mm wide. Fourth toe length 45.7/ 45.9 mm. Rostral scale in contact with three adjacent supra-supralabials. Anteriormost supralabials not in contact below the mental (separated by three granular median scales). Nine supralabials on the right side, eight on the left side. Ten infralabials on both sides. Internasal and rostal scales separated by a row of four small granular scales. Three large and conical frontonasal scales, posterior to and in contact with the internasal. Subdigital lamellae 22/23 under the third toe, 31/32 under the fourth toe. Twenty-six hardly distinguishable femoral pores on the right side (not countable on the left side); 255 tranversal rows of minute scales at midbody. Dorsal crest well developed, ten spiny scales running along the dorsal side of the neck (Cnc), followed by a postnuchal gap of 16 very reduced scales (Cng), 78 spiny scales running along the dorsal side of the trunk (Cdc), then 133 scales on the dorsal side of the tail.

After around six decades of preservation in ethanol, original colour pattern still visible, although the specimen probably became darker during this period. Dorsal and lateral sides of the body dark brown mottled on an irregular yellowish to brownish slightly lighter background. Neck lighter, with an ochre yellowish shade. Lateral side of the head dark brown and ochre yellowish mottled, large conical scales covering the dorsal side of the head whitish, due to the presence of concretions of undetermined origin (likely deposited during the lifetime of the animal). Crest spines mostly chocolate brown, with exception of few series of one to six consecutive dark brown spines corresponding with the darker dots mottling the dorsum. Dorsal and lateral sides of the tail uniformly dark brown, with exception the tail basis yellowish ochre mottled ventrolaterally. Dorsal sides of frontlimbs lighter proximally (brown chocolate and ochre mottled arms) than distally (dark brown forearms), ventral sides light ochre. Dorsal sides of hindlimbs dark brown and ventral sides light ochre. Mental region, ventrum, ventral sides of the limbs and of the tail uniformly light ochre, with exception of a relatively large darker collar and darker ventral sides of manus and pes.