geoemydid, Theobald, 1868

Garbin, Rafaella C., Bandyopadhyay, Saswati & Joyce, Walter G., 2020, A taxonomic revision of geoemydid turtles from Siwalik-age of India and Pakistan, European Journal of Taxonomy 652, pp. 1-67 : 66-67

Key for the identification of adult Indian geoemydid turtles with regard of their shell

We created this key to simplify the identification of geoemydid shell specimens that occur since Miocene and as of today at the Indian subcontinent, belonging to the following species: Batagur kachuga , Batagur dhongoka , Batagur baska , Cuora amboinensis , Cuora mouhotti , Cyclemys gemeli , Cyclemys fusca , Geoclemys hamiltonii , Hardella thurjii , Melanochelys trijuga , Melanochelys tricarinata , Morenia petersi , Pangshura tatrotia , Pangshura sylhetensis , Pangshura tecta , Pangshura smithii , Pangshura tentoria and Vijayachelys sylvatica .

This key was created based on the scoring of characters from our matrix and should be used together with descriptions and illustrations from the literature (Boulenger 1889; Ernst & Barbour 1989; Das 1991, 1994) for correct identification. This key can only be used for adult shells deprived of horny scutes.

1. Carapace with three longitudinal keels.............................................................................................. 2

– Carapace without longitudinal keels or with a median keel only; carapace median length more than 150 mm .............................................................................................................................................. 7

2. Neural bones III-VI hexagonal, with anterior short sides........... Geoclemys hamiltonii (Gray, 1830) – Neural bones III–VI hexagonal, with posterior short sides ............................................................... 3

3. Presence of a plastral hinge ............................................................................................................... 6 – Absence of a plastral hinge; pectoroabdominal sulcus and hyo-hypoplastron suture do not contact. ........................................................................................................................................................... 4

4. Neural bone II hexagonal; pygal bone overlapped by fifth vertebral scute......................................... ........................................................................................... Vijayachelys sylvatica (Henderson, 1912) – Neural bone II octagonal; pygal bone not overlapped by fifth vertebral scute.................................. 5

5. Second to fourth vertebral scutes longer than wide or as long as wide; cervical scute very small; longitudinal gutter on the lateral of the carapace formed by the uplift of peripherals ........................ .......................................................................................... Melanochelys trijuga (Schweigger, 1812)

– Second to fourth vertebral scutes broader than long; first vertebral scute anteriorly wider; cervical scute large, carapace with straight lateral sides ...................... Melanochelys tricarinata Blyth, 1856

6. Carapace ovoid rounded on top; median vertebral keel weakly developed; posterior margin of the carapace not serrated ................................................... Cuora amboinensis (Riche in Daudin, 1801)

– Carapace flattened between second and fourth vertebral scutes; anterior margin of the carapace slightly serrated; posterior margin of the carapace slightly serrated .... Cuora mouhotii (Gray, 1862)

7. Entoplastron intersected by humeropectoral sulcus; plastral buttresses absent or very reduced................................................................................................................ Cyclemys Bell, 1834

– Entoplastron not intersected by humeropectoral sulcus; presence of well developed plastral buttresses............................................................................................................................................ 8

8. Presence of intercostal fontanelle in adults (sexually dimorphic); fourth to sixth marginal scutes can overlap adjacent costal bones ............................................................................................................ 9

– Absence of intercostal fontanelle in adults; fourth to sixth marginal scutes never overlap costal bones ................................................................................................ Morenia petersi Anderson, 1879

9. Long fourth vertebral scute, with its anterior margin over neural IV.............................................. 10 – Short fourth vertebral scute, anterior margin crossing neural V...................................................... 12

10. Fourth vertebral bottleneck anteriorly; neural IV octagonal .......................... Pangshura Gray, 1856 – Fourth vertebral straight laterally; neural IV hexagonal with anterior short-sides...........................11

11. Second vertebral scute with a strong process on posterior margin with invagination into third vertebral; gulohumeral sulcus forming a right angle; humeropectoral sulcus straight........................ ......................................................................................................... Batagur dhongoka (Gray, 1832)

– Second vertebral scute large, as long as wide, with straight lateral margins; third vertebral scute with lateral margin with posterior shorter side .......................................... Batagur kachuga (Gray, 1831)

12. Fourth vertebral scute shorter than second and third vertebrals; anterior plastral margin straight; anal notch absent, or if present, in a wide angle............................................. Batagur baska (Gray, 1830)

– Carapace median keel present; fourth vertebral scute about the same length and width as second and third vertebrals; first vertebral wider posteriorly; strong gular inflection; anal notch rounded ................................................................................................. Hardella thurjii (Gray, 1831)

13. Second vertebral scute much shorter than third vertebral, embracing two neural bones; posterior margin of carapace strongly serrated ......................................... Pangshura sylhetensis Jerdon, 1870

– Second vertebral scute as long as broad, embracing three neural bones; posterior margin of fourth vertebral over neural VIII or posterior............................................................................................. 14

14. Third vertebral scute much longer than wide, with almost parallel lateral margins............................ ......................................................................................................... Pangshura smithii (Gray, 1863) – Third vertebral scute pentagonal, pointed behind............................................................................ 15

15. Second vertebral scute hexagonal to square/rectangular ............ Pangshura tentoria (Murray, 1884) – Second vertebral scute hexagonal, greatly constricted posteriorly.................................................. 16

16. First vertebral scute significantly constricted posteriorly.................... Pangshura tecta (Gray, 1830) – First vertebral scute rectangular or anteriorly constricted ................................................................... ........................................................................................... Pangshura tatrotia Joyce & Lyson, 2010

17. Carapace elongated to rectangular; crown of the head brown, but not lighter than temporal region.. .................................. Cyclemys gemeli Fritz, Guicking, Auer, Sommer, Wink & Hundsdorfer, 2008

– Carapace ovoid when viewed from above; crown of the head lighter than temporal region .............. .................................... Cyclemys fusca Fritz, Guicking, Auer, Sommer, Wink & Hundsdorfer, 2008