AMBLYRHYNCHUS CRISTATUS

Miralles, Aurélien, Macleod, Amy, Rodríguez, Ariel, Ibáñez, Alejandro, Jiménez-Uzcategui, Gustavo, Quezada, Galo, Vences, Miguel & Steinfartz, Sebastian, 2017, Shedding light on the Imps of Darkness: an integrative taxonomic revision of the Galápagos marine iguanas (genus Amblyrhynchus), Zoological Journal of the Linnean Society 181, pp. 678-710 : 696-697

AMBLYRHYNCHUS CRISTATUS

VENUSTISSIMUS EIBL-EIBESFELDT, 1956

( FIGS 6A–D, 7)

Holotype: SMF 49851 . Type locality: ‘ Nordküste der Insel Hood ’ [= Isla Española, N coast].

Paratypes: SMF 49852 , from the type locality, 49853, from ‘ Gardener-Bucht der Insel Hood ’ [= Gardner Bay, Isla Española] , SMF 49853 , from ‘ nördlich von Hood liegenden Insel Gardener ’ [= Isla Gardner , off N coast of Isla Española] .

Specimens examined (N = 30): Española: SFM 49851, 49852, coll. by I. Eibl-Eibesfeldt in 1954, N coast, Gardner Bay (respectively holotype and paratype of A. c. venustissimus). SFM 49854, coll. by I. Eibl-Eibesfeldt in 1954, no exact locality (paratype of A. c. venustissimus). SFM 57413–57416, coll. by I. Eibl-Eibesfeldt in 1957, north-western point of the island. CAS 9308, 9382, 9390, 10960–10969, CAS 11016–11018, coll. by J.R. Slevin in 1906, no exact locality. Gardner (off Española): SFM 49853, HLMD-RA-3046, 3049, 3050, coll. by I. Eibl-Eibesfeldt in 1954, no exact locality (all four paratypes of A. c. venustissimus). Champion (off Floreana ): CAS 11062, coll. by F.T. Nelson in 1906, no exact locality. Floreana : NHM 1876.6.21.1, 1876.6.21.26, coll. by Com. W.E. Cookson, no exact locality.

Geographic distribution: Española, Gardner, Floreana, Champion and very likely their satellite islets. A population of putative migrant specimens that might be assignable to this subspecies has also been put into evidence by MacLeod et al. (2015a) on the southern coast of San Cristóbal ( Fig. 8).

Diagnostic description: Amblyrhynchus cristatus venustissimus is a medium-sized subspecies of marine iguana (mean SVL 264 mm, up to a maximum of 325 mm).Mature males are characterized by a moderately developed crest of spines and moderately conical supracephalic scales. In preservative, the male pattern of coloration is characterized by an olive/grey vertebral stripe (turquoise in life) running over an orange dorsal background coloration (red in life) speckled with large black dots on the flanks. More specifically, this subspecies is also characterized by a high number of lamellae under third (28.8 ± 2.0) and fourth (35.0 ± 2.4) toes and a very high number of scales along the dorsal (114.1 ± 22.9) and caudal crest (161.7 ± 10.6) (see also Figs 4, 6A–D, Table 1).

Redescription of the holotype: SMF 49851. Specimen could not be accessed without destruction of the original, historical jar and therefore was only examined through the glass of the jar; some morphological details could therefore not be reliably scored. Adult male preserved in 70% ethanol, in a very good condition. Hemipenes everted. SVL (≈ 430 mm) shorter than tail length (≈ 430 mm), according to Eibl-Eibesfeldt (1956). Rostral scale in contact with two adjacent supra-supralabials. Anteriormost supralabials in contact below the mental. Nine supralabials on the right side. Eleven infralabials on the right side. Internasal and rostral scales separated by a row of five small granular scales. Three large and conical frontonasal scales, posterior to and in contact with the internasal. Subdigital lamellae 30 under the right third toe. Twenty-four femoral pores on the right side. At midbody 132 transversal rows of minute scales on the right side (left side not visible). Dorsal crest well developed, 17 spiny scales running along the dorsal side of the neck (Cnc), followed by a postnuchal gap of 13 very reduced scales (Cng), 82 spiny scales running along the dorsal side of the trunk (Cdc), then 138 scales on the dorsal side of the tail.

After 62 years of preservation in ethanol, original colour pattern well preserved and sharply contrasted. Background coloration of the dorsal side of the body light dull orange/ochre, with a wide vertebral light olive/ grey stripe running from shoulders to tail insertion. Nuchal region black and strongly contrasting with the rest of the dorsal side. Several large and strongly contrasting black dots sporadically maculating the flanks dorsolaterally, almost completely covering them ventrolaterally. Dorsal and lateral side of the head grey, with deep black nasal, labial and ocular regions. Crest spines mostly greyish, with sporadically few deep black isolated ones. Tail uniformly black (with exception of the pale cream anteriormost part of the ventral side). Dorsal and lateral sides of forelimbs mostly olive/grey, with contrasting black extremeties (distal third of forearms and hand). Dorsal and lateral sides of hindlimbs mostly grey, darker distally than proximally. Ventrum, ventral sides of the limbs and of the tail basis uniformly light cream, with a contrasting deep black thin gular collar. Throat, ventral side of manus and pes darker than ventrum.

AMBLYRHYNCHUS CRISTATUS HASSI EIBL-EIBESFELDT, 1962

( FIGS 5A–C, 7)

Holotype: SMF 57407 . Type locality: ‘ Indefatigable Südküste , westliche Akademiebucht (...) Indefatigable, Galápagos Inseln ’. [= South coast of Isla Santa Cruz , western part of Academy Bay].

Paratypes: SMF 57403–57405 , 57408–57412 , all from the type locality ; SMF 57456 and 57457 (skins only), from Santa Cruz , without further details .

Specimens examined (N = 22): Santa Cruz : SFM 57407, coll. by I. Eibl-Eibesfeldt in 1960, S coast, western Academy Bay (holotype of A. c. hassi). SFM 57405, coll. by I. Eibl-Eibesfeldt in 1957, 3 km W of Academy Bay (paratype of A. c. hassi). SFM 57408–57412, western Academy Bay (paratypes of A. c. hassi). SFM 57456, SFM 57457, 57406, 58100, coll. by I. Eibl-Eibesfeldt in 1957, no exact locality. SFM 60334, coll. by I. Eibl-Eibesfeldt in 1962, no exact locality. HLMD-RA-3066, coll. by G. Scheer in 1954. CAS 10283 , 10787–10791 , coll. by J. R. Slevin in 1905, no exact locality. CAS 87101–87103 , coll. by F. Nied and T. Belland in 1958, Academy Bay. CAS-SUR 18153 , collector unknown, no exact locality .

Geographic distribution: Santa Cruz and very likely its satellite islets, including Seymour Norte ( Fig. 8).

Diagnostic description: Amblyrhynchus cristatus hassi is the largest subspecies of marine iguana (mean SVL 351 mm, up to a maximum of 485 mm). Mature males have a remarkably well-developed crest of spines and moderately conical supracephalic scales. In preservative, the male pattern of coloration is characterized by a dull orange/ochre dorsal background, with many black dots mostly concentrated (and frequently merging together) on the flanks. This subspecies does not seem to present particularly remarkable pholidotic features (see also Figs 4, 5A–C, Table 1).

Redescription of the holotype: SMF 57407 ( Fig. 5B), large adult male preserved in 70% ethanol, in very good condition. SVL (439 mm) shorter than tail length (624 mm). Head 69.3 mm long (HL1), 55.5 mm high and 65.4 mm wide. Fourth finger length 65.9/ 65.5 mm. Rostral scale in contact with three adjacent supra-supralabials (barely with the median one). Anteriormost supralabials not in contact below the mental. Ten supralabials on the right side, nine on the left side. Ten infralabials on the right side, 12 on the left side. Internasal and rostal scales separated by a row of five small granular scales. Four large and conical frontonasal scale, posterior to and in contact with the internasal. Subdigital lamellae 36 under the third toe (on both sides), 32 under the fourth toe (on both sides); 24 femoral pores on the left side (hardly distinguishable on the left side); 279 transversal rows of minute scales at midbody. Dorsal crest well developed, 15 spiny scales running along the dorsal side of the neck (Cnc), followed by a postnuchal gap of 14 reduced scales (Cng), 89 spiny scales running along the dorsal side of the trunk (Cdc), then 143 scales on the dorsal side of the tail.

After 56 years of preservation in ethanol, original colour pattern well preserved and contrasted. Background coloration of the dorsal side of the body black, with an irregularly edged, wide light brown/ ochre stripe running from the anteriormost fifth of the tail to the shoulder, and extending on the lateral sides of the nuchal region. Dorsal and lateral side of the head light brown, with nasal, labial and ocular regions being lighter, almost cream. Crest spines mostly brownish, darker on the anterior half of the body. Dorsal and lateral sides of forelimbs light brown, with the distal third of forearms and hands contrasting blackish. Dorsal and lateral sides of hindlimbs mostly blackish, with exception of the light brown anterior side of thigh. Ventrum, chin, ventral sides of the limbs and of the tail light cream to ochre, with two large and irregular black dots on the chest, and a remarkable contrasting large and triangular deep black gular collar partly extending anteriorly on the throat. Ventral side of manus and pes slightly darker than ventrum.