Iphisa elegans Gray, 1851

Diago-Toro, María F., García-Cobos, Daniela, Brigante-Luna, Giovanni D. & Vásquez-Restrepo, Juan D., 2021, Fantastic lizards and where to find them: cis-Andean microteiids (Squamata: Alopoglossidae & Gymnophthalmidae) from the Colombian Orinoquia and Amazonia, Zootaxa 5067 (3), pp. 377-400 : 394-396

Iphisa elegans Gray, 1851

Distribution: Widely distributed in the Amazonia, including Brazil, Guianas, northern Bolivia, Peru, Ecuador, and Colombia ( Ribeiro-Júnior & Amaral 2017). In Colombia along the Amazonia.

Similar species: Iphisa elegans is easily distinguishable from all other species of gymnophthalmids, alopoglossids and members of skink-like species of the Scincidae family in having two enlarged longitudinal rows of scales on the dorsum and two on the ventral region (no other species present this particular arrangement of enlarged scales in the dorsal or ventral region); and two pairs of chin-shields, the first greatly enlarged (mental cycloid similar in shape to the gular scales in Scincidae ). For a more detailed description see Dixon (1974) and Ávila-Pires (1995).

Remarks: It is also important to mention that I. elegans may correspond to a species complex ( Nunes et al. 2012).

Discussion

Previous authors have widely documented the diversity of alopoglossids and gymnophthalmids in the eastern regions of northwestern South America ( Rivas et al. 2012; Ribeiro-Júnior & Amaral 2017; Torres-Carvajal et al. 2021), however, data from Colombia are normally scarce or absent. This study represents a major attempt in filling the knowledge gaps on the cis-Andean lizards of Colombia, by adding additional pieces to the microteiids puzzle. As well, it is a clear example of the usefulness of biological collections and data curatorship. Of the 29 taxa we reported in the cis-Andean region of Colombia, 26 were found within a single museum, highlighting the importance of the local institutions when conducting comprehensive research in biodiversity. Unfortunately, these local institutions are often invisible for external researchers, in part due to the absence of georeferencing for the older specimens, resulting in a substantial reduction of the taxonomic and geographic representativeness of samples. Our georeferencing work does not only enhance the usability of these records, but also evidences which regions have a better sampling effort (Andean foothills and the southern Amazonas), and which others have been less explored.

Among our data and considering the currently known distribution of the species, we noticed some of them seem to be restricted to certain geographic units. For example, Bachia guianensis , B. heteropa lineata , Cercosaura hypnoides , Gymnophthalmus cryptus , G. marconaterai , Loxopholis caparensis , and L. hexalepis seem to be restricted to the Orinoco basin and/or its foothill. In addition, Alopoglossus avilapiresae , A. buckleyi , B. flavescens group, B. pyburni , Gelanesaurus sp. , Iphisa elegans , L. snethlageae , Potamites ecpleopus , and Tretioscincus oriximinensis have been reported only within the Amazon basin and/or its foothill. Meanwhile, the remaining species ( A. atriventris , A. brevifrontalis , C. oshaughnessyi , Neusticurus medemi , Arthrosaura reticulata , L. parietalis , L. percarinatum , G. speciosus group, and G. leucomystax ) have a wider distribution that includes both regions. The Orinoquian region in Colombia is a mosaic of grasslands, natural savannas, and humid forests, whereas the Amazonian region is mainly characterized by large extensions of humid tropical rainforest, thus the differences in the environmental conditions between these regions may be driving diversification within microteiids, as has been suggested for other lizards ( Ribeiro-Júnior & Amaral 2017; Sheu et al. 2020). However, with our data it is not possible to address if there are historical processes shaping the distribution of the taxa we reported. Even though we fill enormous distribution gaps, the regions where this study is focused are still largely subsampled and specific phylogeographic studies are needed in order to elucidate the biogeographical history of the microteiids in such areas.

Although the aim of this study is not taxonomic, we cannot omit to comment about some taxonomic difficulties we noticed during the process of identification. Neither taxonomy nor the ways to carry out taxonomy are static, but they are particularly challenging when there are large geographic and sampling gaps, as in the case of the cis-Andean region of Colombia. For this reason, we presented this review not only as a list of species, but instead as a comprehensive tool and source of information spotlighting the potential for future research, as well as its constraints. In the remarks we presented brief comments we considered valuable for understanding the groups, and following we will discuss some fundamental issues that require more specific explanation.

For instance, Murphy et al. (2019) elevated both Bachia h. lineata and Bachia h. marcelae to species level, based only on morphological traits from literature without further examination. However, several of these characters overlap among the B. heteropa group, and the diagnosis provided in their study contains inconsistencies making it difficult to interpret. For example, some of the traits they present in Table 2 for “ heteropa ”, “ lineata ” and “ marcelae ” are not consistent with the data they presented in the text diagnosis (e.g., supraocular scales, digits on hindlimbs, and dorsal transversal rows). Furthermore, the unique specimen they examined for B. heteropa (UMMZ 55880) has two digits and not three as they said. Given the above, we consider there is non-conclusive evidence to consider the observed variation in heteropa group as interspecific, and therefore treated B. h. lineata as a subspecies. Further and deeper integrative analyses are required to elucidate the evolutionary relationships within some groups of this genus (as B. heteropa and B. flavescens ), as well as the redefinition of the taxonomic characters that could support diagnoses.

In addition, the continental species of Gymnophthalmus are one of the most problematic cis-Andean species within the Gymnophthalmidae family. This genus possibly harbors cryptic diversity, and their diagnostic traits are not always well-defined, scale counts highly overlap, or are to some extent subject of interpretation. Furthermore, coloration patterns have been one of the main diagnostics traits used to differentiate species within the genus, and although in some cases such as in G. leucomystax and G. marconaterai this is unique, in other species like those in the speciosus group it is less informative. Another problem with coloration as a diagnostic character is when it is described only for in-life specimens or vice versa, since it may be lost or degenerated in preservative. Finally, we found it is particularly difficult to identify specimens within the G. speciosus group because it has historically been considered a complex of species with few or no diagnostic morphological characters ( Vanzolini & Carvalho 1991; García-Pérez & Schargel 2017; Recoder et al. 2018).

The species we reported here constitutes about 40% of the diversity of gymnophthalmids currently known for Colombia, and 24% for the alopoglossids. Only two of the reported species herein are endemic ( Alopoglossus bicolor and Cercosaura hypnoides ), and none is in some IUCN threat category, however, 10 species have not been evaluated or have data deficient. This study allowed us to identify future research opportunities, either for groups that we did not find but will likely be present (e.g., Cercosaura occellata group), and others in which their taxonomy and systematics are complex or not well resolved (e.g., Bachia , Cercosaura , Gymnophthalmus , Loxopholis , and Potamites ).

Identification key

1. Reduced limbs; worm-like body; and no ear-opening......................................................... 2

- Well-developed limbs; lizard-like body; ear opening present................................................... 7

2. Quadrangular dorsal scales............................................................ Bachia gr. flavescens

- Hexagonal to lanceolate dorsal scales..................................................................... 3

3. Keeled dorsal scales...................................................................... Bachia pyburni

- Smooth dorsal scales.................................................................................. 4

4. Interparietal scale absent................................................................ Bachia guianensis

- Interparietal scale present.............................................................................. 5

5. Three digits on the hindlimbs...................................................... Bachia heteropa heteropa

- Two digits on the hindlimbs............................................................................ 6

6. Gulars in six or seven rows.......................................................... Bachia heteropa lineata

- Gulars in five rows.............................................................. Bachia heteropa marcelae

7. With only four fingers; non-movable eyelids............................................................... 8

- With five fingers; with movable eyelids.................................................................. 11

8. Scales around midbody 15, rarely 14; intact bluish tail.................................. Gymnophthalmus cryptus

- Scales around midbody 13, rarely 15; intact tail greyish, reddish to pink, or darkened............................... 9

9. Inconspicuous dorsolateral stripe that fades away towards the midbody; upper lip cream with dark spots or dark brown; cream belly with dark spots; reddish tail............................................... Gymnophthalmus gr. speciosus

- Vivid dorsolateral stripe that extends from the supraocular region to at least the base of the tail; white upper lip; white or cream belly; greyish or salmon-pink tail....................................................................... 10

10. Vivid dorsolateral stripe that extends from the supraocular region to the base of the tail; lateral stripe fades before the groin; greyish tail................................................................. Gymnophthalmus leucomystax

- Well defined dorsolateral stripe that extends from the postorbital region to beyond of the base of the tail; white lateral stripe, similar in width to the dorsolateral stripe, that extends from the ear opening to the tail; salmon-pink tail.......................................................................................... Gymnophthalmus marconaterai

11. First finger very reduced and clawless; ventral scales cycloid arranged in more than two longitudinal rows............................................................................................ Tretioscincus oriximinensis

- First finger well-developed with claw or partially reduced and clawless, with non-cycloid ventral scales; or first finger partially reduced, clawless, with ventral scales cycloid arranged in two longitudinal rows.................................. 12

12. With two longitudinal enlarged rows of scales (wider) on the dorsal region, and two on the ventral; with the first pair of chinshield greatly enlarged...................................................................... Iphisa elegans

- With more than two longitudinal rows of scales on the dorsal and ventral region; the first pair of chin-shields not greatly enlarged............................................................................................. 13

13. Parietal and interparietal scales similar in length, forming a straight line on the posterior edge....................... 14

- Parietals shorter than interparietal scale, forming a curved line on the posterior edge............................... 19

14. Tongue covered with scale-like papillae................................................. Arthrosaura reticulata

- Tongue covered with transversal plicae (folds)............................................................. 15

15. Occipital scales present............................................................................... 16

- Occipital scales absent................................................................................ 17

16. Prefrontals scale present......................................................... Alopoglossus brevifrontalis

- Prefrontal scale absent................................................................ Alopoglossus bicolor

17. Non-granular, keeled and imbricated scales on the flanks of the neck, different in shape to those near the tympanic aperture............................................................................... Alopoglossus avilapiresae

- Small granular scales on the flanks of the neck, similar in shape to those near the tympanic aperture.................. 18

18. Smooth ventral scales............................................................... Alopoglossus buckleyi

- Distinctly keeled to weakly keeled ventral scales......................................... Alopoglossus atriventris

19. All dorsals are small and irregular, similar to those on the sides................................ Neusticurus medemi

- Dorsal scales large and relatively symmetric, or large and intermixed with small irregular scales, normally differing in size to those on sides (except in Loxopholis ).................................................................... 20

20. Heterogeneous dorsal scales, some enlarged, keeled or tuberculate forming longitudinal ridges...................... 21

- Homogeneous dorsal scales, keeled or not but not forming longitudinal ridges.................................... 23

21. Dorsal scales on sides heterogeneous, tubercled and intermixed with small irregular scales........... Potamites ecpleopus

- Dorsal scales on sides homogeneous and smooth........................................................... 22

22. Scales around midbody 45–56; 18–21 lamellae under IV toe; 22–25 femoral pores in males; males and females non different in coloration in the gular region....................................................... Gelanesaurus cochranae

- Scales around midbody 37–48; 15–18 lamellae under IV toe; 19–21 femoral pores in males; males with a white conspicuous patch in the gular region.......................................................... Gelanesaurus flavogularis

23. Dorsal scales different in shape to those on sides, being the dorsals keeled and the flanks smooth; dorsal surface of the forearm smooth............................................................................................ 24

- Dorsal scales similar to those on sides, both keeled; dorsal surface of the forearm keeled........................... 27

24. Quadrangular dorsal scales.......................................................... Cercosaura gr. ocellata

- Hexagonal dorsal scales.............................................................................. 25

25. Single frontonasal scale; hexagonal dorsal scales arranged in transverse and oblique series......... Cercosaura hypnoides Divided frontonasal scale; hexagonal dorsal scales arranged only in transverse series.............................. 26

26. Scales on flanks moderately smaller than dorsals; 27-35 scales around midbody; and absence of preanal pores............................................................................................... Cercosaura argulus

- Scales on flanks distinctly smaller than dorsals; 31-45 scales around midbody; and presence of preanal pores.......................................................................................... Cercosaura oshaughnessyi

27. Smooth or weakly keeled ventral scales.................................................................. 28

- Distinctively keeled ventral scales...................................................................... 29

28. Rhomboid dorsal scales.............................................................. Loxopholis caparensis

- Hexagonal dorsal scales.............................................................. Loxopholis hexalepis

29. Reduced fourth pair of chin-shields..................................................................... 30

- Non-reduced fourth pair of chin-shields.................................................................. 31

30. Third supraocular larger than the second; flanks completely covered by a wide dark band................ Loxopholis sp.

- Second and third supraocular subequal and larger than the others; upper dark stripe on the flanks of 1–3 scales wide, bordered by a lighter color................................................................. Loxopholis percarinatum

31. Large frenocular scale; third supraocular subequal or smaller than the second.................... Loxopholis parietalis

- Small frenocular scale; third supraocular enlarged........................................ Loxopholis snethlageae