Fig 1.
The geology, location, stratigraphy, and magnetostratigraphy of the Ketpurali section and region, northern India.
The correlation of the lithostratigraphy with the magnetostratigraphy (and geochronological boundaries) is provided on the right side. The vertebrate fossil bone horizon is marked with a red star (map and stratigraphic section). The figure is modified from [4].
Fig 2.
Fossil and recent anhingid distal tarsometatarsi.
Anhinga sp. (VPL/RP-KPB1) from India in: (A) Medial view; (B) Dorsal View; (C) Lateral View; (D) Plantar view; and (E) Distal view. Anhinga melanogaster (MVZ 149268) in: (F) Distal view; (G) Dorsal view; and (H) Plantar view. Scale bars equal 1 cm. The specimens are presented at the same size, but the Anhinga melanogaster specimen is larger (bottom scale bar) as compared to the fossil (top scale bar). Abbreviations: abIV–groove for m. abductor digiti IV; df–distal vascular foramen; dp–deep pit on the distal face of metatarsal trochlea IV; lp–collateral ligament pit; mtI–facet for metatarsal I; tIII–metatarsal trochlea III; and tIV–metatarsal trochlea IV.
Fig 3.
The Anhinga tarsometatarsus shaft (KP/KK/BS/102) from the Khetpurali section, India.
(A) Dorsal view. (B) Plantar view. Scale bar equals 1 cm. Abbreviations: abIV–m. abductor digiti IV groove; dif–dorsal infracotylar fossa; ehl–broad notch for the m. extensor hallucis longus; mhc–medial hypotarsal crest; and mtI–metatarsal I facet.
Fig 4.
The proximal tarsometatarsus of fossil and extant Anhingidae with a focus on the hypotarsus.
The Siwalik Hills specimen (KP/KK/BS/101) in: (A) Medial view; (B) Dorsal view; (C) Lateral view; (D) Plantar view; and (E) Proximal view (the missing medial hypotarsal crest is marked by a dashed line). Outline of the tarsometatarsus of Anhinga melanogaster in: (F) Proximal view. Outline of the tarsometatarsus of Anhinga anhinga in: (G) Proximal view. Outline drawings redrawn from Harrison’s [37] type A and B morphologies. Scale bar equals 1 cm. Abbreviations: fdl–canal for the m. flexor digitorum longus tendon; fhl–canal for the m. flexor hallucis longus tendon; fp–groove for the m. flexor perforatus digiti II tendon; fpp–groove/canal for the m. flexor perforans et preforatus digiti II tendon; ie–intercotylar eminence; lc–lateral cotyle; lcl–impression for the lateral collateral ligament; lhr–lateral hypotarsal ridge (ridge bounding the groove for the m. fibularis longus tendon); mc–medial cotyle; mf–groove for the m. fibularis tendon; mhc–medial hypotarsal crest; pf–proximal vascular foramen; rr- retinacular ridges; and tc–attachment for the m. tibialis cranialis.
Table 1.
Distal tarsometatarsus measurements (mediolateral width) of fossil and extant anhingids (in mm).