Fig. 3 (8)
Tetraclita dumortieri Fischer, 1866: 434, pl. 1 figs 1 a–c
Synonymy: Tetraclita dumortieri var. alta Locard 1878: 9, pl. 18 figs 1–2. Tesseropora sp. Carriol 2005: 119, pl. 1 figs 5–7.
Other references: Tetraclita dumortieri Locard 1878: 9, pl. 18 fig. 3; Douxami 1896: 260. Tesseropora dumortieri Carriol 1993: 710, pl. 1 figs 1 –4, 9– 10 (first description of the scuta).
Non: De Alessandri 1906 b, p. 290, pl. 9 fig. 32 a–b; De Alessandri 1907, p. 197, fig. 9.
Type locality: Miocene from the Jardin des Plantes of Lyon and from the Balmes of Saint-Fons, Rhône, France.
Occurrence: Ferrière-Larçon, Indre-et-Loire, France; faluns of Middle Miocene age.
Material: MNHN A 24748: left scutum.
In addition to the figured scutum, some unregistered plates have been observed: a rostrum, two pieces of undetermined plates, and a carina.
Measurements: MNHN A 24748: occludent margin 4.0 mm, basal margin 2.7 mm.
Description: Scutum: exterior without radial furrow, too eroded to estimate prominence of growth ridges; interior: articular ridge not extending beyond tergal margin; articular furrow thin, shallow; adductor ridge very prominent, separated from articular ridge, crossing plate from apex to basal margin; pit for adductor muscle well-marked, oval, shallow depression; lateral depressor muscle and rostral muscle pits with conspicuous crests.
Discussion: The oldest representative of Tesseropora is T. isseli (De Alessandri, 1894) from the Oligocene of Italy. Two species have been previously recorded in France: T. dumortieri (Fischer, 1866), Miocene, Rhône and Isère; T. sulcata Carriol, 1993, Pliocene, Manche. These two species can be distinguished from each other only by the morphology of the scutum (Carriol 1993).
Tesseropora specimens previously found from the Middle Miocene of the faluns of Touraine (Carriol 2005) consist of two scuta and a lateral plate, but the poor preservation of the two scuta did not allow a specific attribution of these specimens. With the discovery of a scutum from Ferrière-Larçon, the specific assignment of the Tesseropora from the faluns of Touraine is established.
Stratigraphic and geographic range: Miocene (France: Rhône and Isère), Middle Miocene (France, faluns of Touraine).