Tropidurus imbituba, Kunz, Tobias Saraiva & Borges-Martins, Márcio, 2013

Kunz, Tobias Saraiva & Borges-Martins, Márcio, 2013, A new microendemic species of Tropidurus (Squamata: Tropiduridae) from southern Brazil and revalidation of Tropidurus catalanensis Gudynas & Skuk, 1983, Zootaxa 3681 (4), pp. 413-439 : 422-426

Tropidurus imbituba sp. nov.

( Figs. 6–10 )

Holotype: Adult male, UFRGS 5932; collected on the 10th of January 2011 by T. S. Kunz and R. F. Bressan, in the rocky seashore of Praia da Vila (Morro do Farol; 28º14’20’’S / 48º39’10’’W), municipality of Imbituba , Santa Catarina, Brazil.

Paratypes: 10 males ( MCP 18947-49; UFRGS 5044, 5092, 5203, 5225, 5302, 5354, 5358) and 14 females ( MCP 18944-46; UFRGS 5043, 5045, 5093, 5164-65, 5205-07, 5357, 5545-46), all collected in the type locality by T. S. Kunz between December 2008 and January 2011.

Diagnosis. Tropidurus imbituba sp. nov. is distinguished from all other species of the torquatus group, except from T. catalanensis and T. torquatus , by having folds and pockets of the type “A” (sensu Rodrigues 1987). From T. catalanensis it differs in lower dorsal scales counts; from T. catalanensis and T. torquatus , by the distinctive bronze or orange coloration of the venter and sides of the trunk and neck in adult males (yellow in the chest and throat in T. catalanensis and white or cream in T. torquatus ).

In relation to T. torquatus , the new species presents broad overlap in meristic characters with specimens from the Cerrados, differing in coloration (venter orange-bronze in T. imbituba sp. nov.; white or cream in T. torquatus ). From specimens of the mountain ranges of Rio de Janeiro, it is well distinguished by meristic characters (dorsals, gulars, SAB); and from the coastal ones, it differs in attaining larger body size (SVL of the larger male of the new species is 125.8 mm, while the larger male of the coastal populations of eastern Brazil attained 107 mm.).

Description of holotype. Adult male, 122.7 mm SVL; intact tail, 206 mm; head length 28.2 mm; head width 25 mm; head height 17.1 mm; frontal scales of the head irregular and convex; nasals in contact with rostral and separated by a minimum of two scales; 3 canthals; anteriormost canthal separated from supralabials by one row of lorilabials; 9 infralabials; 5 enlarged supralabials to below center of eye, followed by 6 elongated scales to the commissure of mouth, of which the posterior five are very small; 5th supralabial in contact with the subocular; 7 spines in the preauricular fringe; 5 angulate, enlarged postmentals; first postmental in contact with first infralabial; first postmental not contacting one another; subocular separated from the preauricular fringe by a minimum of 10 scales; interparietal irregular, longer than wide; 10 scales in the medial line between interparietal and rostral; superciliary composed by two series, the anterior one with 5 scales and the posterior one with 2, separated by one scale overlapped by scales of the two series; two rows of enlarged supraoculars, 9 in the first row and 6 in the second row ( Figure 9 ).

Antehumeral fold present; two pockets under oblique neck fold; three axillary granular pockets; inguinal granular pocket present; scales of the sides of the neck much smaller than the adjacent dorsals; 100 keeled and mucronate dorsals; 94 scales around midbody; 81 ventrals; 53 gular scales; 20 scales on the dorsum of tibia; 25 subdigital lamellae under fourth finger; 31 subdigital lamellae under fourth toe; subdigital lamellae tricarinate; black, thick and strongly curved claws; femoral and preanal patches of black pigmented glandular scales present; without midventral patch of black pigmented glandular scales.

Variation within type series: Head length 21–25% of SVL; tail length 60–64% of total length; largest male 125.8 mm SVL; largest female 86.7 mm SVL; smaller gravid female (with oviductal eggs) 74.9 mm SVL.

Frontal scales of head convex in adults; 2–4 scales between nasals; rostral contacting nasals in 44% of specimens; 10–13 scales between rostral and interparietal; 2–3 scale rows of enlarged supraoculars, generally three; 7–9 enlarged supraoculars in the first row; 5–6 supralabials to below centre of eye, generally 5, followed by 4–8 (generally 5) small elongated scales to the commissure of mouth; supralabials contacting subocular in 68% of specimens, generally with 5th and less frequently with 6th, 7th or both; 7–10 infralabials, generally 8–9; 6–8 spines in the preauricular fringe; 8–11 scales between the subocular and the preauricular fringe, generally 9–10; mental polygonal, followed by 3–5 enlarged postmentals; first postmentals contacting one another in only one specimens (UFRGS 5354); 2–4 canthals, generally 3; 43–55 gular scales (mean 50.8 ± 3.0, n=25).

Two mite pockets under the oblique neck fold, the upper pocket is well developed and the lower one is poorly developed; antehumeral fold present; 2–3 axillary pockets, generally 3; inguinal granular pocket present; 27–33 subdigital lamellae under fourth toe (mean 30 ± 1.5, n=25); 20–26 scales on the dorsum of tibia (mean 22.5 ± 1.4, n=25). 99–113 dorsals in males (mean 104.9 ± 4.6, n=11) and 102–116 in females (110.6 ± 3.7, n=14); 87–109 SAB in males (mean 99.3 ± 5.6, n=11) and 98–112 in females (mean 106.3 ± 4.2, n=14); 70–89 ventrals (78.0 ± 5.3, n=25).

Color in life. Dorsal color is light gray, cryptic in relation to the local rocks, with a pattern of black paravertebral patches and numerous cream colored spots along the trunk and limbs; in large males the spots in the sides of the trunk and neck may be bronze or orange; some females are almost uniform gray; black antehumeral band occupying 5–11 scale rows, separated (rarely not) from the opposite one by up to 17 scales (mean 10.9 ± 4.0); venter bronze in adults, cream in juveniles; adult males have femoral and preanal patches of black pigmented glandular scales; some large males present few black pigmented glandular scales on venter, but none presented a well developed midventral patch; adults have black gular patches; chin cream; dark gular reticulations enclosing cream blotches in juveniles but usually not evident in adults.

Etymology. The specific epithet is derived from the Tupí-guarani language, meaning “ imbé in abundance” (imbé = a name used for some species of lianas and other plants, and tuba = abundance) and refers to the type locality, the municipality of Imbituba , the only place where the species is known to occur. The name is used as an indeclinable noun in apposition.

Distribution. Restricted to a small and isolated granitic hill known as “Morro do Farol”, situated between Praia da Vila (Vila’s Beach) and the Port of Imbituba , in the municipality of Imbituba , southern coast of the state of Santa Catarina (28º14’S / 48º39’ W). The hill is about 1200 x 500 m large and reaches 100 m a.s.l. and is surrounded by a large sandy coastal plain. Most of the adjacent plain is currently occupied by the city of Imbituba . Vegetation of Morro do Farol is composed mostly by shrubs and low herbs, similar to that of the adjacent open restingas, with many rocky outcrops, and by portions of Atlantic Forest with low canopy (about 10 m tall) due to the strong ocean influence, mainly on the higher portions and on the western slope. The surrounding plain was originally covered by open restingas and sand dunes near the ocean, turning gradually westward to lowland Atlantic Forest. There are, also, many swamps in these plains ( Figures 11–12 ).

Remarks. During the period of this study (2009–2011), we made several field expeditions to the coast of Santa Catarina searching for new Tropidurus populations. These expeditions included all rocky seashores near the Morro do Farol, Imbituba (e.g. Itapirubá, 28º20’24’’S, 48º42’11’’W; Pedra do Frade, 28º25’23’’S, 48º44’26’’W; Canto da Praia do Porto, 28º12’36’’S, 48º39’49’’W; Barra de Ibiraquera, 28º08’33’’S, 48º38’30’’W), including also a small island with an isthmus of only 80 m from Morro do Farol and distant places such as Farol de Santa Marta (28º36’13’’S, 48º48’47’’W) and Morro dos Conventos (28º56’03’’S, 49º21’47’’W). All these expeditions failed in localizing new populations.

The distribution pattern of T. imbituba is uncommon among lizards from the Atlantic Coast of South America and we are unaware of other species of lizards with a similar distribution in that region. We believe that the sandy plains and dunes surrounding Morro do Farol represent barriers to the dispersal of these lizards.

Morro do Farol is a relatively well preserved area, neighboring a marine conservation unit, the “Área de Proteção Ambiental da Baleia Franca ”. However, there is a great amount of tourists in summer and it is adjacent to the Port of Imbituba which is expected to expand in a few years. A portion of the western slope of Morro do Farol is already occupied by activities of the port. Considering the extremely restricted distribution and a expected decline of habitat quality and extension, T. imbituba can be categorized as Critically Endangered (CR), according to criteria B1a+b(iii) (known and estimated area of occurrence <100 km 2 and presence of relevant human impacts) of the IUCN Red List ( IUCN 2001).

Figures

FIGURE 6. Holotype (UFRGS 5932) of Tropidurus imbituba sp. nov. in life (SVL 122.7 mm).

FIGURE 7. Dorsal (left) and ventral (right) views of the holotype (UFRGS 5932) of Tropidurus imbituba sp. nov.

FIGURE 8. Lateral view of head of the holotype (UFRGS 5932) of Tropidurus imbituba sp. nov. Freshly killed adult male (head length 28.2 mm).

FIGURE 9. Dorsal view of head of the holotype of Tropidurus imbituba sp. nov. (UFRGS 5932; head length 28.2 mm). Scale bar = 10 mm.

FIGURE 10. Tropidurus imbituba sp. nov. at the rocky seashore (Morro do Farol) of Praia da Vila, Imbituba, Santa Catarina, Brazil. Adult male (not collected).

FIGURE 11. Morro do Farol, Imbituba, the type locality of Tropidurus imbituba sp. nov. Praia da Vila (Vila’s Beach) on the left and Port of Imbituba right behind the hill. The city of Imbituba is in the background. Photograph courtesy of the Port of Imbituba.

FIGURE 12. Rocky seashore at Praia da Vila, Imbituba, Brazil. Arrow indicates the exact place where most of the type series was collected, including the holotype.