Editorial Type:
Article Category: Research Article
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Online Publication Date: 30 Nov 2022

Dwarves in a Big World: Two New Species of Tropiocolotes (Squamata: Gekkonidae) from the Sahara Desert, with the First Detailed Skull Description of the Genus

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Page Range: 396 – 421
DOI: 10.1670/20-103
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ABSTRACT

The Sahara Desert is the largest ecoregion in Africa, but its biodiversity in general, and reptile biodiversity in particular, are only superficially known and probably grossly underestimated. The dwarf-lizard genus Tropiocolotes is widely distributed in the region. The genus' taxonomy is plagued by serious nomenclatural problems that have led to a series of misidentifications of specimens in collections and in the literature. Analyzing variation in meristic and osteological characters of the Saharan species of Tropiocolotes, we found individuals from Algeria with unique external and internal morphological characters that distinguish them from all other species in the genus. We present a detailed account of these characters and describe two new species of Tropiocolotes from Algeria. Additionally, we provide the first detailed description of skulls of the genus, and designate a neotype to T. steudneri.

Copyright: Copyright 2022 Society for the Study of Amphibians and Reptiles 2022
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Fig. 1.
Fig. 1.

Principal Component Analysis (PCA) of meristic characters between specimens of Tropiocolotes algericus (pink), T. tripolitanus occidentalis (purple), T. tripolitanus tripolitanus (green), T. steudneri (yellow), T. chirioi sp. nov. (blue), and T. tassiliensis sp. nov. (red).

Fig. 2.
Fig. 2.

(A) Dorsal and (B) ventral views of the holotype of Tropiocolotes chirioi sp. nov. (MNHN-RA-1997.5086). Scale bar: 1 cm.

Fig. 3.
Fig. 3.

(A) Dorsal, (B) ventral, and (C) lateral views of the head and neck of the holotype of Tropiocolotes chirioi sp. nov. (MNHN-RA-1997.5086). Scale bar: 1 cm.

Fig. 4.
Fig. 4.

(A) Holotype of Tropiocolotes chirioi sp. nov. (MNHN-RA-1997.5086), (B) holotype of T. algericus (MCZ-R 27485), (C) holotype of T. tripolitanus tripolitanus (ZMB 9668A), (D) holotype of T. tripolitanus occidentalis (BMNH 1946.8.24.49), (E) holotype of T. chirioi sp. nov. (MNHN-RA-1997.5086), (F) holotype of T. somalicus (BMNH 1946.8.23.55), (G) holotype of T. t. tripolitanus (ZMB 9668A), and (H) holotype of T. t. apoklomax (CAS 103209).

Fig. 5.
Fig. 5.

Dorsal view of three specimens of T. chirioi sp. nov. (A–C) and two specimens of T. tassiliensis sp. nov. (D, E): (A) MNHN-RA-1997.5088, (B) MNHN-RA-1973.1306, (C) ZFMK 2351, (D) ZFMK 19853, and (E) ZFMK 2352.

Fig. 6.
Fig. 6.

Micro-CT images of the skull of a paratype of Tropiocolotes chirioi sp. nov. (ZFMK 2350) in (A) dorsal, (B) lateral, and (C) ventral views: boc (basioccipital); cb (compound bone); co (coronoid); d (dentary); ecp (ectopterygoid); epp (epipterygoid); f (frontal); j (jugal); m (maxilla); n (nasal); otoc (otooccipital); pa (parietal); pal (palatine); pref (prefrontal); pbas (parabasiphenoid); pm (premaxilla); pof (postorbitofrontal); po (prootic); pt (pterygoid); q (quadrate); sm (septomaxilla); so (sclerotic ring); soc (supraoccipital); sq (squamosal); sta (stapes); v (vomer). Scale bar: 1 mm.

Fig. 7.
Fig. 7.

Micro-CT images of the skull of a paratype of Tropiocolotes chirioi sp. nov. (ZFMK 2350) in (A) anterior and (B) posterior views: boc (basioccipital); cb (compound bone); co (coronoid); d (dentary); ecp (ectopterygoid); epp (epipterygoid); f (frontal); j (jugal); m (maxilla); n (nasal); otoc (otooccipital); pa (parietal); pref (prefrontal); pm (premaxilla); pof (postorbitofrontal); po (prootic); pt (pterygoid); q (quadrate); rp (retroarticular process of compound bone); sm (septomaxilla); soc (supraoccipital); sq (squamosal); v (vomer). Scale bar: 1 mm.

Fig. 8.
Fig. 8.

Micro-CT images of the skull of a paratype of Tropiocolotes chirioi sp. nov. (ZFMK 2350) in dorsal view: (A) mandibulae removed, (B) ectopterygoids, frontal, jugals, mandibulae, maxillae, parietals, postorbitofrontals, prefrontals, premaxilla, and squamosals removed, (C) all previously mentioned bones plus braincase (fused parabasiphenoid, basioccipital, supraoccipital, prootics, and otooccipitals), epipterygoid, and septomaxillae removed: boc (basioccipital); ecp (ectopterygoid); epp (epipterygoid); f (frontal); j (jugal); m (maxilla); n (nasal); otoc (otooccipital); pa (parietal); pal (palatine); pref (prefrontal); pbas (parabasiphenoid); pm (premaxilla); pof (postorbitofrontal); po (prootic); pt (pterygoid); q (quadrate); sm (septomaxilla); soc (supraoccipital); sq (squamosal); sta (stapes); v (vomer). Scale bar: 1 mm.

Fig. 9.
Fig. 9.

Micro-CT images of the skull of a paratype of Tropiocolotes chirioi sp. nov. (ZFMK 2350) in ventral view: (A) mandibulae removed, (B) braincase (fused parabasiphenoid, basioccipital, supraoccipital, prootics, and otooccipitals), mandibulae, maxillae, premaxilla, pterygoids, and vomers removed, (C) all previously mentioned bones plus ectopterygoids, jugals, epipterygoids, quadrates, and septomaxillae removed: boc (basioccipital); ecp (ectopterygoid); epp (epipterygoid); f (frontal); j (jugal); m (maxilla); n (nasal); pa (parietal); pal (palatine); pref (prefrontal); pbas (parabasiphenoid); pm (premaxilla); pof (postorbitofrontal); pt (pterygoid); q (quadrate); sm (septomaxilla); sq (squamosal); sta (stapes); v (vomer). Scale bar: 1 mm.

Fig. 10.
Fig. 10.

Micro-CT images of the mandibulae of a paratype of Tropiocolotes chirioi sp. nov. (ZFMK 2350) in (A) dorsal, (B) ventral views, and left mandibula in (C) lateral, and (D) medial views: cb (compound bone); co (coronoid); d (dentary); rp (retroarticular process of compound bone); sp (splenial). Scale bar: 1 mm.

Fig. 11.
Fig. 11.

(A) Dorsal view of the head of Tropiocolotes chirioi sp. nov. (MNHN-RA-1997.5086), (B) dorsal view of the head of T. algericus (MCZ-R 27485), and (C) T. algericus in life, showing differences in snout general shape (shorter and wider snout in T. algericus than in T. chirioi sp. nov.). Photo in life: P. Geniez.

Fig. 12.
Fig. 12.

Distributional records of Tropiocolotes chirioi sp. nov. and T. tassiliensis sp. nov., and the populations of other African species of Tropiocolotes used in comparative analyses (external morphology and color pattern). Stars: type-localities (holotypes); square: type-locality (lectotype); pentagon: type-locality (neotype); circle: examined specimens; circle with dot: photograph.

Fig. 13.
Fig. 13.

(A) Dorsal and (B) ventral views of the holotype of Tropiocolotes tassiliensis sp. nov. (CAS 138662). Scale bar: 1 cm.

Fig. 14.
Fig. 14.

(A) Dorsal, (B) ventral, and (C) lateral views of the head and neck of the holotype of Tropiocolotes tassiliensis sp. nov. (CAS 138662). Scale bar: 1 cm.

Fig. 15.
Fig. 15.

(A) Holotype of Tropiocolotes tassiliensis sp. nov. (CAS 138662), (B) neotype of T. steudneri (ZFMK 33843), (C) T. steudneri (ZFMK 33856), (D) holotype of T. nubicus (FMNH 256865).

Fig. 16.
Fig. 16.

Specimen of Tropiocolotes nubicus in life, photographed by C. Brito in the Tassili n'Ajjer Mountains, Algeria. Credit: C. Brito.

Fig. 17.
Fig. 17.

(A) Dorsal and (B) ventral views of the neotype of Tropiocolotes steudneri (ZFMK 33843). Scale bar: 1 cm.

Fig. 18.
Fig. 18.

(A) Dorsal, (B, C) lateral, and (D) ventral views of the head and neck of the neotype of Tropiocolotes steudneri (ZFMK 33843). Scale bar: 1 cm.

Contributor Notes

2 Corresponding author. E-mail: majunior@gmail.com
3

Authors contributed equally.

Accepted: 02 Jun 2022
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