Maracaiba, Hedges & Conn, 2012

Hedges, S. Blair & Conn, Caitlin E., 2012, A new skink fauna from Caribbean islands (Squamata, Mabuyidae, Mabuyinae) 3288, Zootaxa 3288 (1), pp. 1-244 : 118-119

Genus Maracaiba gen. nov.

Maracaibo Skinks

Type species. Mabuya meridensis Miralles , Rivas, & Schargel , 2005:3 .

Diagnosis. Species in this genus are characterized by (1) frontoparietals, two, (2) supraciliaries, four, (3) supraoculars, four, (4) prefrontal contact, absent (or contact very rarely in M. meridensis ), (5) parietal contact, present (occasionally no contact in M. zuliae ), (6) rows of nuchals, one, (7) dorsals + ventrals, 127 (one specimen examined by us, using our counting method), (8) total lamellae, not counted, (9) a dark middorsal stripe, present and absent, (10) dark dorsolateral stripes, absent (see Remarks), (11) a dark lateral stripe, present, and (12) dark ventral striping, absent. The range of maximum body sizes among the species is 77–101 mm SVL ( Table 2).

Maracaiba is distinguished from Brasiliscincus , Manciola , and Notomabuya by having dark (versus pale) palms and soles. The presence of two frontoparietals (unfused) separates this genus from Exila , Notomabuya , and Panopa (one frontoparietal). The presence (versus absence) of dark lateral stripes distinguishes this genus from Alinea . Maracaiba is separated from Brasiliscincus and Varzea by having a higher number of dorsals + ventrals (127 versus 113–126). From Capitellum , Maracaiba differs in having four supraciliaries (versus 5–6). From Marisora , it differs (weakly) by having a high number of dorsals (63 versus 50–63; only three of 80 Marisora examined with 63 dorsals). From Copeoglossum , Maracaiba differs by having parietal contact (versus usually no contact) and a higher number of dorsals + ventrals (127 versus 105–120). In having four supraoculars, Maracaiba is separated from two genera with three supraoculars: Aspronema (rarely four) and Mabuya (rarely two or four). It differs from Manciola in having fewer dorsals + ventrals (127 versus 136–141). The presence of a single nuchal row separates this genus from Exila and Panopa (2–5 nuchal rows) and from most Spondylurus (usually 2–3 rows, rarely one). It also differs from Spondylurus in having poorly-defined dorsolateral dark and pale stripes (welldefined in Spondylurus ). Orosaura has what appears to be a pair of irregular, dark nape stripes or lines of spots immediately adjacent to the pale dorsolateral stripes (Miralles et al. 2009) whereas this pattern is lacking in Maracaiba . Maracaiba differs from Psychosaura in having a typical mabuyine head shape (subacuminate) versus

Distribution. Species in this genus are found in northern Venezuela, in the general region of Lago de Maracaibo; Fig. 8C . Their altitudinal ranges differ greatly, with M. meridensis 1300 –2200 m and M. zuliae 0–1500 m.

Etymology. The generic name ( Maracaiba ) is a feminine noun and refers to the distribution of the genus, centered around Lago de Maracaibo in northern Venezuela.

Remarks. Maracaiba is most closely related (91% bootstrap support) to the three other genera in the northern portion of the distribution of Mabuyinae : Mabuya , Marisora , and Orosaura ( Fig. 5 ). Together, along with Alinea (see Discussion), they form the Northern Clade. The two included species in Maracaiba cluster closely (100% bootstrap support). In the original descriptions of those species, emphasis was placed on their number of dark stripes, in both distinguishing them from one another and from other species: Maracaiba meridensis was characterized as having seven stripes and M. zuliae four stripes ( Miralles et al. 2005b; Miralles et al. 2009b). Although we have limited experience with these species, having examined only one M. meridensis, our inspection of the photos and illustrations of M. meridensis ( Miralles et al. 2005b) leads us to conclude that it is more dorsally spotted than M. zuliae but otherwise does not have dark dorsolateral stripes (as are normally scored as stripes in mabuyines). The narrow dark middorsal stripe also appears to be weakly defined. We are not questioning the species level distinction of M. meridensis and M. zuliae but rather the count of stripes and how it relates to characterizing and diagnosing this genus. More specimens need to be surveyed for the diagnostic traits that we mention above, but we consider this genus to be well-diagnosed when considering both the molecular and morphological data.

Figures

FIGURE 5 (continued on the next page)

FIGURE 8. Distribution of the 16 genera of Neotropical skinks, Family Mabuyidae, Subfamily Mabuyinae. (A) Genera occurring in the greater Caribbean region. (B) Genera occurring exclusively in South America. (C) Additional genera occurring in South America, including one with representatives on Caribbean islands.