Canrightia foveolata E.M.FRIIS, P.R.CRANE, K.R.PEDERSEN, M.M.MENDES et J.KVAČEK, 2022

Friis, Else Marie, Crane, Peter R., Pedersen, Kaj Raunsgaard, Mendes, Mário Miguel & Kvaček, Jiří, 2022, The Early Cretaceous Mesofossil Flora Of Catefica, Portugal: Angiosperms, Fossil Imprint 78 (2), pp. 341-424 : 347-349

Canrightia foveolata E.M.FRIIS, P.R.CRANE, K.R.PEDERSEN, M.M.MENDES et J.KVAČEK sp. nov.

Text-figs 3a–f , 4a–i

Holotype. S174249 (Catefica sample 49; figured Text-fig. 3a–f ).

Plant Fossil Names Registry Number.

PFN002785 (for new species).

Paratypes. S175179, S265998, S266057, S266107 (Catefica sample 49), S266042 (Catefica sample 154), S175178 (Catefica sample 242).

Repository. Palaeobotanical Collections , Department of Palaeobiology, Swedish Museum of Natural History, Stockholm, Sweden .

Etymology. From Latin: fovea (pit) referring to the densely pitted surface of the endotesta.

Type locality. Catefica (39° 03ʹ 30ʺ N; 09°14ʹ 30ʺ W), between the villages of Catefica and Mugideira, about 4 km south of Torres Vedras, Portugal .

Type stratum and age. Almargem Formation, Early Cretaceous (Aptian-early Albian).

D i a g n o s i s. Fruit obovoid with a broad hypanthium and two pendent seeds. Perianth of six tepals. Contact surface between the two seeds flat; external surface rounded. Crystals evenly distributed in the cells of the endotesta. Surface of endotesta foveolate with shallow foveae arranged in more than 30 closely packed longitudinal rows. Fruit wall particularly thick apically over the seeds.

Distinguishing features. The new species is assigned to the extinct genus Canrightia based on the berry-like fruit with pendent, orthotropous seeds that have an endotestal-endotegmic seed coat and a crystalliferous endotesta. Canrightia foveolata is distinguished from C. resinifera (see above), and from C. elongata from the Torres Vedras mesofossil flora ( Friis et al. 2019a), mainly by the densely pitted and grooved surface of the endotesta. Seeds of C. foveolata also have crystals that are of more or less of similar size and that are evenly distributed in the endotestal cells, whereas in C. resinifera and C. elongata larger crystals are concentrated close to the outer surface of endotesta. Canrightia foveolata is also two-seeded, as are most specimens of C. resinifera from the Famalicão locality, while fruits of C. resinifera from the Catefica locality typically have three to five seeds and C. elongata has three seeds.

Canrightia foveolata is further distinguished from the two other species of Canrightia by the well-developed soft tissue of the fruit wall above the seeds. Canrightia foveolata may also be distinguished from the two other species by the larger number of perianth parts, but as the perianth is known for only one specimen of C. foveolata , and only a few specimens of C. resinifera , the range of tepal numbers in Canrightia is not fully established.

A pitted surface of the endotesta is also present in seeds of Canrightiopsis E.M.FRIIS, G.W.GRIMM, M.M.MENDES et K.R.PEDERSEN and Kvacekispermum E.M.FRIIS, P.R.CRANE et K.R.PEDERSEN , two other extinct genera of chloranthoid affinity ( Friis et al. 2015a, 2018b), but both of these genera have one-seeded fruits and a much thicker endotestal seed coat.

Dimensions. Length of fruit: 1.7 mm; maximum width of fruit: 1.6 mm; length of seed: 0.85–1.05 mm; maximum width of seed: 0.6–0.9 mm.

Description and remarks. The new species is based on a single fruit, containing two seeds ( Text-fig. 3a–f ). There are also several isolated seeds ( Text-fig. 4a–i ). The fruit and two of the isolated seeds were studied using SRXTM. The fruit is partly abraded, and although the stigmatic region is missing, the fruit is otherwise well preserved in its apical part. There is a swollen rim about halfway up the fruit with six, small poorly developed tepals that are best preserved on one side of the fruit ( Text-fig. 3a ). Five vascular bundles are preserved in the hypanthium, each extending to a tepal and their symmetry indicates that a sixth bundle has been lost where the fruit wall is abraded ( Text-fig. 3d ). The fruit wall is particularly thick in the region above the seeds and consists mainly of isodiametric cells ( Text-fig. 3a–c ).

The seeds are broadly elliptical, crescent-shaped in lateral view, slightly pointed at the micropylar end and rounded at the chalazal end ( Text-figs 3b , 4a–d, f ). Where the two seeds meet, their faces are flattened, but with a prominent chalaza that projects towards the face where the seeds meet (Textfig. 4b, d). The opposite faces are rounded ( Text-figs 3c, d , 4b, c, e ). In the isolated seeds, the outer cells of the seed coat are abraded exposing the surface of the endotesta, which is characterized by numerous small pits arranged in more than 30 shallow, closely-spaced, longitudinal grooves ( Text-fig. 4a–d ).

In the fruit the exotesta of the seeds is partly preserved and consists of thick-walled, isodiametric cells. The endotesta is thin (about 30 µm) in the region between the two seeds, but thicker (about 55 µm) in the chalazal region and toward the outer surfaces ( Text-fig. 3c, e, f ). The exotesta is so tightly appressed to the tissue of the fruit wall that the two tissues are sometimes difficult to delimit. The endotesta consists of palisade-shaped cells that are infilled with fibrous material in which there are abundant casts of cubic crystals. The casts of these crystals are distributed more or less evenly within the cells ( Text-figs 3f , 4e–i ).

The inner integument is three cell layers thick. It consists of an outer epidermis, a middle layer of thick-walled and slightly longitudinally elongated cells, and an inner epidermis that develops into an endothelium of thin-walled and radially elongated cells ( Text-figs 3c, d , 4e, f, h ).

The stigmatic area is not preserved and no pollen was observed on the surface of the fruit.

Affinity and other occurrences. The relationships of Canrightia foveolata , as for Canrightia resinifera , arelikelyclosetothebaseofextantChloranthaceae (see above). Canrightia foveolata is currently known only from the Catefica locality.

Figures

Text-fig. 3. Synchrotron radiation X-ray tomographic microscopy (SRXTM) images of fruits of Canrightia foveolata sp. nov.; Catefica locality, Portugal. a) Volume rendering of fruit showing prominent rim around the middle of the fruit with reduced tepals (arrowheads) and partly abraded fruit wall exposing the pitted endotesta surface of one of two seeds (arrow); note two of the vascular bundles (vb) extending from the base of the fruit to the tepals; b) Voltex of fruit showing prominent rim around the fruit (arrowhead) and dense precipitation of crystals in the endothelium cells of one of the two seeds in the fruit; c) Longitudinal section of fruit (orthoslice yz0520) showing the inferred hypanthium rim (arrow head) and two seeds, one with a dense precipitation of crystals; note the prominent endothelium cells (asterisks) of the inner integument and the well-developed fruit wall above the seeds; d) Transverse section through basal part of fruit and seeds close to the micropyle (orthoslice xy0312) showing partly abraded fruit wall with five vascular bundles (vb) and details of the seed coat with endotesta (oi-end) surrounding the tegmen consisting of an outer epidermis (ii-o), middle layer (ii-m) and a distinct inner epidermis (endothelium) consisting of radially elongated cells (asterisk); e) Transverse section (orthoslice xy1680) through apical part of the fruit close to chalaza showing the tips of two seeds; note the endotesta (oi-end) surrounded by thick-walled cells of the exotesta (oi-o); f) Transverse section (orthoslice xy1485) through fruit in the region of the hypanthium rim showing sections through the two seeds close to the chalazal region; note endotesta (oi-end) surrounded by larger cells of exotesta (oi-o) and fruit wall (fr). Specimen, Catefica 49-S174249 (holotype, a–f). Scale bars = 300 Μm (a–c, e, f), 100 Μm (d).

Text-fig. 4. Synchrotron radiation X-ray tomographic microscopy (SRXTM) images of seeds of Canrightia foveolata sp. nov.; Catefica locality, Portugal. a–d) Volume renderings of abraded seeds in ventral (a), lateral (b, d) and apical (c) views showing the slightly protruding chalaza (arrows) and dense longitudinal grooves with shallow pits in the surface of the endotesta; e) Transverse section of seed (orthoslice xy0665) showing the irregular grooved surface of the endotesta (oi-en) and the tegmen comprised of two layers of thick-walled cells that surround the cells of the prominent endothelium (asterisk); f) Longitudinal section (orthoslice xz1195) through seed showing the thin-walled endothelium cells (asterisk) surrounded by the thicker cells of the outer tegmen and endotesta; g) Longitudinal section (orthoslice yz0727) through seed showing outlines of angular crystals evenly distributed in cells of the endotesta (oi-en); note the outer epidermis of the tegmen (ii-o) composed of thick-walled cells; h) Longitudinal section (orthoslice xz0940) of seed showing details of the chalazal region with course of the vascular bundle (vb), cells of the prominent endothelium (asterisk), crystalliferous endotesta of the outer integument (oi-en) and the distinct thick walled cells of the outer cells of the tegmen (ii-o); i) Longitudinal and tangential section (orthoslice yz0542) through the endotesta (oi-en) showing the outlines of densely spaced crystals. Specimens, Catefica 242-S175178 (a–c, e–h), Catefica 49-S175179 (d, i). Scale bars = 300 Μm (a–d), 100 Μm (e, f, h, i), 50 Μm (g).