SIRENIA, Illiger, 1811

Bell, Christopher J., Godwin, William, Jenkins, Kelsey M. & Lewis, Patrick J., 2020, First fossil manatees in Texas, USA: Trichechus manatus bakerorum from Pleistocene beach deposits along the Gulf of Mexico, Palaeontologia Electronica (a 47) 23 (3), pp. 1-16 : 6

SIRENIA , gen. et sp. indet. ( Figure 3 )

SHSU 1-236. Distal rib, 23.2 cm curvilinear length; maximum diameter 5.6 cm ( Figure 3 ). Collected on McFaddin Beach; from the Joe Liggio collection.

SHSU 1-233. Distal rib fragment, 14.2 cm curvilinear length; maximum diameter is 3.8 cm. Collected on Caplen Beach; from the Kit Herrington Collection.

SHSU 1-234. Distal rib fragment, 10.4 cm curvilinear length; maximum diameter is 4.2 cm. Collected on McFaddin Beach; from the Joe Liggio collection. TxVP 44211-1. Midshaft rib fragment, maximum preserved length is 7.1 cm; maximum diamter is 4.5 cm. Collected from locality 44211, “just off the Inglesides, in the Channel.”

Remarks. The rib fragments are pachyosteosclerotic, a condition typical of derived aquatic sirenians ( Domning and de Buffrénil, 1991; de Buffrénil et al., 2010) and associated with maintenance of buoyancy ( Domning and de Buffrénil, 1991). SHSU 1-236 shows marked expansion along the central portion of the rib shaft, and tapering at the distal end, both characteristic of the ribs of extant sirenians.

Figures

FIGURE 3. SHSU 1-236, distal rib fragment. Scale bar equals 2 cm.