Iodes reidae, Del Rio, Thomas & De Franceschi

Rio, Cédric Del & Franceschi, Dario De, 2020, Icacinaceae fossil fruits from three sites of the Paris Basin (early Eocene, France): local diversity and global biogeographic implications, Geodiversitas 42 (2), pp. 17-28 : 20-22

Iodes reidae

Del Rio, Thomas & De Franceschi emend. Del Rio & De Franceschi ( Fig. 2 J-Q)

EMENDED DIAGNOSIS. — Endocarp elliptical with a reticulate pattern of angular to rounded and thin ridges, delimiting 9-19 polygonal areoles per face, with few or no freely ending ridgelets. Endocarp possessing a symmetrical pair of horn-like protrusions, compressed on the keel, positioned eccentrically and subapically. Endocarp wall 0.25-0.34 mm thick (excluding ridges, 0.8-1.1 mm including ridges). Length of endocarp: 9.2-10.9 mm, width: 6.7-7.6 mm.

STRATIGRAPHY. — Late Paleocene.

ADDITIONAL STRATIGRAPHY. — Early Eocene.

TYPE LOCALITY. — Rivecourt (Oise, France).

ADDITIONAL LOCALITY. — Passy (Oise, France).

SPECIMENS. — MNHN.F.44737 .

LATIN CORRECTION OF THE SPECIES NAME. — The suffix -ae replace the suffix -ii in order to be more in accordance with the authors ‘first etymology (this species is in memory of Eleanor M. Reid, Del Rio et al. 2019a).

DESCRIPTION (PASSY SPECIMEN)

Endocarp bilaterally symmetrical, unilocular, single-seeded, elliptical, laterally compressed in the plane of symmetry, lenticular in transverse section; length 10.9 mm, width 7.1 mm. Outer part of the endocarp with a reticulate pattern of angular to rounded and thin ridges with four longitudinal ridges and two inter-ridges, delimiting 19 polygonal areoles per face ( Fig. 2O ), with few or no freely ending ridgelets ( Fig. 2J, L ); a keel surrounding the endocarp in the plane of symmetry with one part thicker, containing a vascular bundle embedded in the endocarp wall ( Fig. 2K, Q ). Presence of a symmetrical pair of horn-like protrusions compressed on the keel, positioned eccentrically and subapically on the apical endocarp faces, each with a central pit ( Fig. 2L ); Endocarp wall 0.28-0.34 mm thick (excluding ridges, 0.83-1.1 mm including ridges, Fig. 2P ). Cell walls and inner endocarp surface decayed.

SYSTEMATIC AFFINITY

This single specimen corresponds in almost all characters to the species Iodes reidae from the Rivecourt site. The ratio of ridge thickness/wall thickness is characteristic of I. reidae : a thin endocarp wall with much thicker/higher ridges. Furthermore, the reticulation pattern and the shape of the horn-like protrusions are very similar. The diagnosis of I. reidae was emended to encompass the size and areole number of this new species which are very close too. The anatomical characters are not preserved in this specimen.

Figures

FIG. 2. — A-I, Iodes passiciensis Del Rio & De Franceschi, sp. nov. (MNHN.F.44736): A, lateral view of an endocarp showing the reticulum pattern of rounded and thin ridges; B, dorsal view showing the keel, surrounding the endocarp; C, lateral view of second face of the endocarp; D, basal view; E, apical view; F, magnification showing the pores abraded; G, SEM view of wall and ridges in transversal section;H, SEM view of rounded papillae; I, same with magnification. J-Q, Iodes reidae Del Rio, Thomas & De Franceschi (MNHN.F.44737): J, lateral view of endocarp showing the reticulum pattern of rounded ridges; K, dorsal view showing the keel, surrounding the endocarp; L, lateral view of second face of endocarp; M, basal view; N, apical view; O, magnification showing the areoles from the reticulation of ridges; P, SEM view of wall and ridges in transversal section; Q, SEM view of the trace left by the vascular bundle embedded in the endocarp wall. Scale bar: A-E, 5 mm; O-Q, 1 mm; J-N, 10 mm; G, 500 µm; F, 100 µm; H, 50 µm; I, 10 µm.