Icacinicaryites sp., Del Rio C. & De Franceschi, 2020

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 : 25

Icacinicaryites sp.

( Fig. 5 )

STRATIGRAPHY. — Cuisian.

LOCALITY. — Prémontré ( France).

SPECIMEN. — MNHN.F.44741 .

DESCRIPTION

Fossil bilaterally symmetrical, elliptical; unilocular and singleseeded, length 8.8 mm, width 7.6 mm. Apex slightly asymmetrical, base rounded, symmetrical. Outer part of locule cast with reticulate pattern of rounded ridges; face of locule cast with 3-4 longitudinal ridges enclosing 6-9 polygonal areoles on each lateral face with few or no freely ending ridgelets; a keel surrounds the locule cast in the plane of symmetry (ṙ); cellular details unknown.

REMARKS

Only one specimen represents the Icacinaceae in this outcrop. We found no thicker part on the keel which suggests that this specimen is a locule cast rather than the complete endocarp. In the absence of apparent anatomical preservation, we choose to include this specimen in the genus Icacinicaryites without species name. This specimen could be close to Iodes multireticulata sensu Reid & Chandler (1933) but with fewer areoles. It may correspond to Iodes rigida from Le Quesnoy site, but the reticulation pattern does not match. This specimen seems to have a unique morphology despite the lack of anatomical characters.

OVERVIEW OF ICACINACEAE

FROM THE PARIS BASIN

Here we review all the accepted occurrences of the Icacinaceae from the Paris Basin ( Table 1 ). In addition to fruits

from Passy, Belleu and Prémontré studied here, we include the fruits from Rivecourt (Paleocene; Del Rio et al. 2019a) and Le Quesnoy (early Eocene, Del Rio et al. 2019b) and a flower from Le Quesnoy ( Del Rio et al. 2017).

Occurrences of triporate and echinate pollen belonging to the Compositoipollenites genus (with Icacinaceous affinity) have been described for the Paris Basin. Compositoipollenites medius Krutzch & Vanhoorne, 1977, Compositoipollenites minimus Krutzch & Vanhoorne, 1977 and Compositoipollenites rhizophorus burghasungensis (Murriger & Pflug, 1952) Thomson & Pflug, 1949 were found in the Le Quesnoy site and the Paleocene of Guitrancourt ( Cavagnetto 2000, Kedves 1970). Moreover, Compositoipollenites minimus was also found in Nointel (early Eocene, Oise; see Kedves 1970) and Compositoipollenites rhizophorus (R. Potonié, 1934) R. Potonié, 1960 at Paris Austerlitz (late Eocene, Paris; see Kedves 1970). However, some author consider that we have not enough data from other families that also have echinate pollen to confidentially conclude about these affinities ( Manchester et al. 2015). We decided to follow the same caution and we do not include them in our analysis. No leaves or woods remains have been attributed to Icacinaceae in the Paris Basin.

Figures

FIG. 5. — Icacinicaryites sp.(MNHN.F.44741): A, lateral view;B, dorsal view showing the keel; C, other lateral view; D, apical view;E, basal view.Scale bar:5 mm.