Iodes passiciensis Del Rio & De Franceschi 2020
Creators: name: Rio, Cédric Del
name: Franceschi, Dario De
Publisher: name: Zenodo
Year: 2020
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Magnoliopsida
Icacinales
Icacinaceae
Iodes
Iodes passiciensis

description: Iodes passiciensis
Del Rio & De Franceschi, sp. nov. (Fig. 2 A-I)
Endocarp bilaterally symmetrical, unilocular, elliptical, lenticular in transverse section; outer surface of the endocarp with a reticulate pattern of rounded and thin ridges with a channel on the median apical part, enclosing 25-29 polygonal areoles per face, with few or no free-ending ridgelets; a keel surrounds the fruit in the plane of symmetry with the thicker side containing a vascular bundle embedded in the endocarp wall. Endocarp possesses a small pair of pores. Inner endocarp surface densely covered with regularly spaced and sessile rounded papillae. Endocarp length c. 7 mm, width c. 4.4 mm.
HOLOTYPE. — MNHN.F.44736.
PARATYPE. — MNHN.F.44739.
ETYMOLOGY. — From the latin name of Passy (Passicum) where the fossil taxon was recovered.
STRATIGRAPHY. — Early Eocene.
TYPE LOCALITY. — Passy (France).
DESCRIPTION
Endocarp bilaterally symmetrical, unilocular, elliptical, lenticular in transverse section; length 6.7-7.2 mm, width c. 4.4 mm, thickness c. 4.4 mm. Outer part of the endocarp with a reticulate pattern of rounded and thin ridges with a channel on the median apical part of its surface corresponding to the trace left by the outer vasculature at the boundary between endocarp and mesocarp; 4-5 irregular longitudinal ridges and some inter-ridges, enclosing 25-29 polygonal areoles per face with few or no freely ending ridgelets (Fig. 2A, C); a keel surrounds the fruit in the plane of symmetry with one part thicker containing a vascular bundle embedded in the endocarp wall (Fig. 2B). Endocarp possessing a small pair of pores, positioned eccentrically and subapically on the apical endocarp (Fig. 2F); endocarp wall 0.15-0.21 mm thick (excluding ridges, 0.34-0.44 mm thick including ridges, Fig. 2G). Cell walls of the endocarp not preserved. Inner endocarp surface densely covered with regularly spaced and sessile rounded papillae, 0.011 -0.019 (avg. 0.016 mm) in diameter (Fig. 2H, I).
REMARKS
This species is represented by only two lignitic endocarps.
SYSTEMATIC AFFINITY
Iodes passiciensis, sp. nov. is unique in having the following combination of characters: 25-29 areoles with no freely ending ridgelets, small pores and rounded ridges. This species differs from I. reidae Del Rio, Thomas & De Franceschi in having a pattern of reticulation more developed and a smaller size (both not overlapping). Iodes passiciensis, sp. nov. differs from I. tubulifera Del Rio, Thomas & De Franceschi in having rounded ridges and a smaller size. The horn-like protrusions are also more obvious in I. tubulifera and protrude sub-apically whereas we have pores in this new species. This species is similar to I. rivecourtensis Del Rio, Thomas & De Franceschi in having rounded ridges, small pores and a reticulation pattern developed without free ending ridgelets. However, I. passiciensis, sp. nov. is smaller, with more areoles, and with a smaller endocarp wall and ridges. This species differs from I. sinuosa Del Rio, Thomas & De Franceschi in having distinctly rounded ridges (despite the absence of cell wall preservation) and a more strongly developed reticulate pattern, but is close in other aspects. Iodes parva Del Rio, Thomas & De Franceschi is close to this species but is smaller, with fewer areoles and has horn-like protrusions that clearly protrude out from the endocarp wall. It also differs from Iodes occidentalis S.E. Allen, Stull & Manchester in lack of free-ending ridges and pores. Iodes multireticulata Reid & Chandler (Stull et al. 2016) lacks pores and are bigger than those of I. passiciensis, sp. nov. Iodes germanica Knobloch & Mai is slightly smaller (4-5 mm) than this new species and apparently lacks pores (Knobloch & Mai 1986). Iodes bilinica (Ettingshausen) Stull, Adams, Manchester & Collinson differs by the presence of frequent free-ending ridges. The length and width of I. eocenica Reid & Chandler (Stull et al. 2016) are almost double those of I. passiciensis, sp. nov. Iodes acutiformis Chandler possesses an acute apex (Chandler 1962), unlike I. passiciensis, sp. nov., but seems to be very similar in other characters despite having a more relaxed reticulation pattern. Iodes brownii (Berry) Stull, Adams, Manchester & Collinson and I. corniculata Reid & Chandler have a similar number of areoles but are larger in size. The channel on the median apical part of the ridges is also found in the species I. rigida Del Rio & De Franceschi from Le Quesnoy site. However, the ridge structures are different with I. rigida that showing an I-beam-like shape of ridges (almost rectangular). All these considerations allow us to describe a new species from these two specimens, which is close to I. sinuosa and I. parva described from the Rivecourt site.
description: Published as part of 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, pp. 17-28 in Geodiversitas 42 (2) on pages 19-20, DOI: 10.5252/geodiversitas2020v42a2, http://zenodo.org/record/3696913