1	Skin moist, no scales present; tail absent	Amphibians / Anurans (frogs), 2
–	Skin dry, covered with scales; tail present	Reptiles, 3
2	Small species (adult snout-vent length 25-35 mm); tympanal region blackish; hind limbs with distinct dark bands; relatively small eyes; iris silvery; adult males with distinct femoral glands on ventral surface of thighs; only on Mayotte	Blommersia sp. (MA)
–	Medium-sized species (adult snout-vent length 35-56 mm); tympanal region beige to brown; hind limbs without or with indistinct dark bands; relatively large eyes; iris reddish; adult males without femoral glands on ventral surface of thighs; only on Mayotte	Boophis sp. (MA)
3	Limbs and external ear opening absent	Serpentes (snakes), 4
–	Limbs and external ear opening present	Lacertilia (lizards), 11
4	Worm–like snakes with burrowing habits; very small, total length ca. 100-250 mm; scalation and coloration uniform all over body; eyes absent or only visible as small black spots covered by scales	Typhlopidae, 5
–	Typical snakes, ground- or tree-dwelling; medium-sized to large, adult total length > 50 cm; one distinctly enlarged row of ventral shields and 17–23 dorsal scale rows at midbody; pupil of eyes clearly visible	other families, 7
5	Maximum total length 181 mm; 20 midbody scale rows; 261-364 total middorsal scales; superior nasal suture visible dorsally	Ramphotyphlops braminus (AN, GC, MA, MO)
–	Not as above	Typhlops, 6
6	Maximum total length 245 mm; 22 midbody scale rows; 414-485 total middorsal scales Typhlops comorensis (AN, GC)
–	Extremely small, known total length 68-70 mm; 18 midbody scale rows; 384-408 total middorsal scales; species poorly known	Typhlops sp. (GC)
7	Dorsal coloration with dark and bright crossbands, dark bands at least twice as broad as bright bands; less than 100 ventral scales; only on Grande Comoro, occurrence in need of confirmation	Lycodon aulicus (Natricidae, GC – UNCONFIRMED)
–	Dorsal coloration other than 7 A); more than 150 ventral scales	Lamprophiidae, 8
8	Robust, ground-dwelling and digging snake; rostral scale directed upwards; total length of adults up to 150 cm; 23 dorsal scale rows Leioheterodon madagascariensis (GC)
–	Slender, terrestrial or arboreal, non-digging snakes; rostral scale not directed upwards; total length of adults up to 100 cm; 17-19 dorsal scale rows	9
9	Pupil round; head not broader than neck; coloration dorsally grayish, ventrally bright with small dark spots on each ventral scale; ground-dwelling	Liophidium mayottensis (MA)
–	Pupil vertical; head distinctly broader than neck; ground- or tree-dwelling	Lycodryas, 10
10	Mostly 19 dorsal scale rows (sometimes 17) at midbody; coloration sexually dimorphic, males grayish, sometimes with dark spots or blotches, iris gray, females uniformly orange or brown, iris brownish	Lycodryas sanctijohannis (AN, GC, MA, MO)
–	17 dorsal scale rows at midbody, coloration brown with dark crossband	Lycodryas gaimardii (MA – UNCONFIRMED)
11	Eyes largely covered with skin and moving independently; prehensile tail; tong-like hands and feet with two or three lateral fingers opposing inner fingers	Chamaeleonidae, 12
–	Eyes not covered with skin; no prehensile tail; fingers and toes not fused	other families, 13
12	Snout-vent length maximum 77 mm in males, 54 mm in females; rostral crests with very distinctly enlarged scales, fusing anteriorly and reaching or exceeding snout tip; distinctly elevated parietal crest; gular crest with distinctly enlarged cones	Furcifer cephalolepis (GC)
–	Snout-vent length maximum 104 mm in males, 63 mm in females; rostral crests with weakly enlarged scales, poorly elevated, diminishing posterior to snout tip; parietal crest visible, but not elevated; gular crest poorly developed	Furcifer polleni (AN, MA)
13	Head dorsally with enlarged, symmetrical scales distinct from scales following posteriorly	Scincidae / Lacertidae, 14
–	Head dorsally with scales similar to those following posteriorly	other families, 21
14	Dorsal scales granular, ventral scales cycloid and overlapping, forming a distinct collar of enlarged scales in the throat region	Meroles knoxii (Lacertidae, AN – UNCONFIRMED)
–	Scales uniformly cycloid and overlapping	Scincidae, 15
15	Body cylindrical, head and tail not clearly distinct from body; limbs small; coloration light brown with dark brown spots	Amphiglossus johannae (AN, GC, MA, MO)
–	Body fusiform, distinct neck, tail distincly less broad than body, lizard-like appearance; ground coloration dark brown to black	16
16	Medium-sized, often robust lizards, total length up to more than 200 mm; scale rows around midbody 28 to 39	Trachylepis, 17
–	Small lizards, less than 100 mm total length; dorsoventrally depressed; coloration blackish, often with white stripes; scale rows around midbody 21 to 29; only in rocky intertidal regions	Cryptoblepharus boutonii, 18
17	Common lizard; coloration dark with patterns of brighter spots; never with white stripes	Trachylepis comorensis (AN, GC, MA, MO)
–	Coloration blackish with two white lateral stripes	Trachylepis striata (AN)
18	Coloration uniformly black	Cryptoblepharus boutonii ater (GC)
–	White stripes present	19
19	Black with two white lines along the body	Cryptoblepharus boutonii mohelicus (MO)
–	More than two white lines present	20
20	Black with four white lines along the body, tail sometimes bluish	Cryptoblepharus boutonii mayottensis (MA)
–	Black with five white or yellowish lines along the body, tail often blue	Cryptoblepharus boutonii degrijsiii (MO)
21	Ventral surface of fingers and toes with adhesive lamellae, allowing movement on vertical surfaces; total length never exceeding 160 mm; usually not ground-dwelling	Gekkonidae, 22
–	Adhesive lamellae absent; total length up to 500 mm; ground-dwelling, climbing only on rough surfaces; robust lizards	other families, 38
22	Dorsal ground color green, sometimes in shades of olive or brownish, often with pattern in red; pupil round; diurnal	Phelsuma, 23
–	Dorsal ground color brown or grey, green and red colors absent; pupil vertical; nocturnal	31
23	Dark lateral stripe along body present	24
–	No dark lateral stripe present	25
24	Neck dorsally without dark stripes, limbs dorsally marbled with bright spots, tail dorsally with dark spots	Phelsuma comorensis (GC)
–	Neck dorsally with three dark stripes, limbs dorsally not marbled, tail with narrow dark crossbands	Phelsuma nigristriata (MA)
25	Dorsal ground color rather green with olive, brown or turquoise shades than deep green	26
–	Dorsal ground color deep green	27
26	Flanks with brighter spots, dorsum dark green or brown, with orange median line (sometimes interrupted), sometimes with blue blotch on neck	Phelsuma robertmertensi (MA)
–	No bright spots on flanks, often red dots on dorsum, no median line, tail often bluish	Phelsuma dubia (AN, GC, MA, MO)
27	Numerous small yellowish or golden spots dorsally in neck region and on tail; three large red blotches posteriorly on dorsum	Phelsuma laticauda laticauda (AN, MA)
–	Neck and tail not yellowish or golden, dorsum with numerous smaller red dots and spots	28
28	Blue spot on neck; gular region uniformly bright	Phelsuma pasteuri (MA)
–	No blue color elements dorsally; gular region with more or less visible pattern in the form of a “V”	Phelsuma v-nigra, 29
29	Ventral side yellow, dorsal side green with relatively large red dots	Phelsuma v-nigra v-nigra (MO)
–	Ventral side whitish, dorsal red dots smaller	30
30	Dorsal side green to bluish, small red dots, sometimes with red median line	Phelsuma v-nigra comoraegrandensis (GC)
–	Dorsal side green, red dots very small, sometimes forming a reticulated pattern or absent	Phelsuma v-nigra anjouanensis (AN)
31	Scales rather large, cycloid, overlapping, can be shed when touched; tubercles and striped color patterns absent	Geckolepis maculata (AN, GC, MA, MO)
–	Scales small, granular, in part tubercular; sometimes with striped color pattern	32
32	Adhesive lamellae covering entire ventral side of digits, in double rows of several pads each; when resting, ventral side of body usually in contact with substrate; colors brown during day, grayish, whitish or pinkish at night	Hemidactylus / Gehyra, 33
–	Adhesive lamellae only in two pads near tips of the toes; when resting, ventral side of body usually lifted from substrate; colors always brownish other genera	37
33	Body and tail smooth, no tubercles present; coloration grey, sometimes pinkish	Gehyra mutilata(UNCONFIRMED)
–	Body and tail covered with tubercles; coloration grey to brownish; very common in urban areas and plantations, rare in natural habitats	Hemidactylus, 34
34	Maximum snout-vent length of adults 55 mm; 2 to 8 rows of tubercles along the back, with 7 to 24 tubercles per row; dorsal side of body mostly uniformly white, beige or yellowish at night, pattern of dark stripes and spots visible during the day	Hemidactylus frenatus (AN, GC, MA, MO)
–	Pattern of dark stripes and spots mostly also visible at night; 8 or more rows of tubercles along the back, with 21 or more tubercles per row	35
35	Maximum snout-vent length of adults 51 mm; dorsal side covered with relatively prominent brown and whitish tubercles; 3 to 5 dorsal rows of brown spots often visible; 14 to 17 rows of tubercles along the back, with 23 to 30 tubercles per row	Hemidactylus parvimaculatus (AN, MO)
–	Snout-vent length of adults up to more than 51 mm; dorsal side usually with pattern of brighter and darker colors, but no whitish tubercles present	36
36	Maximum snout-vent length of adults 59 mm; original tail with whorls of spiny, enlarged scales extending far into the distal half of the tail; males with 25 to 32 femoral pores; 8 to 16 rows of tubercles along the back, with 25 to 37 tubercles per row; cranial depression extending anteriorly from between the eyes less distinct than in 36 B)	Hemidactylus mercatorius (AN, GC, MA, MO)
–	Maximum snout-vent length 85 mm; original tail with whorls of spiny, enlarged scales largely restricted to the proximal part of the tail; males with 41 to 59 femoral pores; 8 to 14 rows of tubercles along the back, with 21 to 31 tubercles per row; cranial depression extending anteriorly from between the eyes more distinct than in 36	Hemidactylus platycephalus (AN, GC, MA, MO)
37	Small, slender geckos, maximum snout-vent length 40.8 mm; flanks darker than dorsum, with sharpest contrast in head region; never with crossbands on body	Ebenavia inunguis (AN, GC, MA, MO)
–	Medium-sized geckos with robust heads, maximum snout-vent length 66.9 mm; four bright crossbands on dorsum, best visible at night; coloration of flanks not clearly distinguished from that of dorsum	Paroedura sanctijohannis (AN, GC, MA, MO)
38	Neck with crest of spiny scales; scales on tail similar to those on body; males with contrasting black and orange color pattern	Agama agama (GC)
–	Crest of spiny scales on neck absent; tail with enlarged scales, spiny	Oplurus cuvieri comorensis (GC)