North American Recent Soft-shelled Turtles (Family Trionychidae) Part 6

ARTIFICIAL KEY TO NORTH AMERICAN SPECIES AND SUBSPECIES OF THE GENUS TRIONYX

1. Septal ridges present; tubercles on anterior edge of carapace present or absent 2

Septal ridges absent; anterior edge of carapace lacking tubercles or raised prominences 19

2. Plastral area a uniform dark slate or blackish; soft parts of body blackish having large pale marks dorsally; carapace having large black blotches, often fused along margin, on pale background, and many well-defined longitudinal ridges _ T. ferox_, p. 479

Combination of characters not as above; ventral surface whitish, blackish flecks or blotches sometimes present 3

3. Carapace having pattern of white dots, or black ocelli and/or spots; carapace sometimes gritty resembling sandpaper 4

Carapace uniform pale brownish or grayish, or having mottled and blotched pattern, contrasting or not; white dots or tubercles, black ocelli and/or spots may be present; carapace not gritty 10

4. Carapace having pattern of black ocelli and/or spots; numerous, conspicuous whitish spots or tubercles absent 5

Carapace having pattern of white dots that are sometimes surrounded by small black ocelli; small black dots may be interspersed among larger white dots 7

5. Carapace having two or more marginal lines, these often diffuse and interrupted; black spots sometimes ocellate or bacilliform, or interspersed among smaller black dots; postocular and postl.a.b.i.al stripes usually united _spinifer asper_, p. 502

Carapace having only one dark marginal line; pattern of black ocelli or spots; postocular and postl.a.b.i.al stripes usually not united 6

6. Carapace having prominent ocelli, which are much larger near the center than at the sides _spinifer spinifer_, p. 489

Carapace having numerous small, dark spots, sometimes small ocelli, which are not much larger near the center than the sides _spinifer hartwegi_, p. 497

7. White spots on anterior third of carapace; white spots on carapace often surrounded by narrow blackish ocelli; small black dots sometimes interspersed among white spots _spinifer guadalupensis_, p. 517

White spots absent on anterior third of carapace, or small and inconspicuous; white spots not surrounded by narrow blackish ocelli 8

8. Pale rim of carapace narrow, partly obscured; over-all dorsal coloration (including soft parts of body) dark and lacking pattern; few, small, white tubercles confined to posterior third of carapace _ater_, p. 528

Pale rim distinct, without markings; soft parts of body dorsally not uniformly dark; many white tubercles usually contrasting on pale carapace 9

9. White spots confined to posterior third of carapace; ground color of carapace usually pale brown or tan, sometimes darker; a dark, slightly curved, line connecting anterior margins of orbits; postocular stripe usually interrupted leaving pale, blotch behind eye; pale rim of carapace four or five times wider posteriorly than laterally _spinifer emoryi_, p. 510

Small white spots on posterior half of carapace gradually decreasing in size anteriorly, often indistinct or absent on anterior third of carapace; pale rim of carapace no more than three times wider posteriorly than laterally _spinifer pallidus_, p. 522

10. Marginal ridge present; carapace having ill-defined dark blotches on uniform grayish, lacking whitish tubercles or well-defined black spots or ocelli; pale rim of carapace absent; tubercles on anterior edge of carapace resembling flattened hemispheres; anterior parts of plastron often visible in dorsal view; postocular stripe, if present, having thick, blackish borders _ferox_, p. 479

Marginal ridge absent 11

11. Carapace uniform pale brownish, lacking mottled and blotched pattern, white dots, black ocelli or spots 12

Carapace having mottled and blotched pattern, contrasting or not; white spots or tubercles, black ocelli or spots may be present 13

12. Pale rim of carapace four or five times wider posteriorly than laterally; dark, straight or slightly curved, line connecting anterior margins of orbits _spinifer emoryi_, p. 510

Pale rim of carapace no more than three times wider posteriorly than laterally _spinifer pallidus_, p. 522

13. Rear margin of carapace usually roughened by fine corrugations, edge often ragged; pale rim absent; carapace having dark brown-blackish, mottled and blotched pattern; anterior edge of carapace more or less smooth having scarcely elevated prominences; posterior part of plastral area and especially ventral surface of carapace having numerous black marks _ater_, p. 528

Rear margin of carapace smooth, edge entire; usually some evidence of pale rim 14

14. White, rounded tubercles or spots usually evident posteriorly on carapace, sometimes indistinct; black ocelli or spots lacking in center of carapace, sometimes present at sides; shape of tubercles on anterior edge of carapace variable 15

White spots or tubercles absent; margin of carapace usually having black ocelli or spots; tubercles on anterior edge of carapace equilateral or conical, not low and flattened 17

15. White spots often present on anterior half of carapace; tubercles on anterior edge equilateral and wartlike, or less elevated, not conical _spinifer guadalupensis_, p. 517

White spots usually absent on anterior half of carapace, sometimes indistinct; shape of tubercles on anterior edge of carapace variable 16

16. White spots absent on anterior half of carapace; tubercles on anterior edge of carapace low, scarcely elevated, never equilateral or conical; mottled and blotched pattern often not contrasting; ground color of carapace sometimes dark; pale rim of carapace four or five times wider posteriorly than laterally; dark, straight or slightly curved, line connecting anterior margins or orbits _spinifer emoryi_, p. 510

White spots sometimes indistinct on carapace, or few, small spots present on posterior half of carapace; tubercles on anterior edge of carapace equilateral and wartlike or conical; mottled and blotched pattern usually contrasting; pale rim less than three times wider posteriorly than laterally _spinifer pallidus_, p. 522

17. Carapace having evidence of more than one dark marginal line, and scattered, black spots or ocelli _spinifer asper_, p. 502

Carapace having only one, dark, marginal line 18

18. Carapace having small black spots, lacking large interrupted ocelli _spinifer hartwegi_, p. 497

Carapace having small black spots interspersed among larger, interrupted ocelli _spinifer spinifer_, p. 489

19. Carapace having pattern of dusky spots, sometimes short lines 20

Carapace lacking pattern of dark spots or lines, having a mottled and blotched pattern 21

20. Pattern of circular spots, lacking short lines or bacilliform marks; spots sometimes slightly ocellate; no pale stripes on snout _muticus calvatus_, p. 539

Pattern of dots, or dots and short lines; pale stripes on snout, at least just in front of eyes _muticus muticus_, p. 534

21. Mottled and blotched pattern usually contrasting; ill-defined, blackish blotch absent behind eye _muticus muticus_, p. 534

Mottled and blotched pattern usually not contrasting; ill-defined, dark blotch may be present behind eye _muticus calvatus_, p. 539

Systematic Account of Species and Subspecies

=Trionyx ferox= (Schneider)

Florida Softsh.e.l.l

Plates 31 and 32

_Testudo ferox_ Schneider, Naturg. Schildkr., p. 330, 1783 (based on Pennant, Philos. Trans. London, 61 (Pt. 1, Art. 32): 268, pl. 10 [figs. 1-3], 1772).