Kvacekispermum costatum E.M.FRIIS, P.R. CRANE et K.R.PEDERSEN, 2019

Friis, Else Marie, Crane, Peter R. & Pedersen, Kaj Raunsgaard, 2019, The Early Cretaceous Mesofossil Flora Of Torres Vedras (Ne Of Forte Da Forca), Portugal: A Palaeofloristic Analysis Of An Early Angiosperm Community, Fossil Imprint 75 (2), pp. 153-257 : 183-185

Kvacekispermum costatum E.M.FRIIS, P.R. CRANE et K.R.PEDERSEN sp. nov.

Text-fig. 19a–c

H o l o t y p e. Designated here. S174098 (Torres Vedras sample 38; figured Text-fig. 19a ).

P l a n t F o s s i l N a m e s R e g i s t r y N u m b e r.

PFN000457 (for new species).

P a r a t y p e. Designated here. S174099 (Torres Vedras sample 38).

R e p o s i t o r y. Palaeobotanical Collections , Department of Palaeobiology, the Swedish Museum of Natural History, Stockholm, Sweden .

E t y m o l o g y. From Latin: costatus referring to longitudinal ridges on the surface of the endotesta.

T y p e l o c a l i t y. Torres Vedras (NE of Forte de

Forca; 39°06′13″ N, 9°14′47″ W).

T y p e s t r a t u m a n d a g e. Lower member of the Almargem Formation; Early Cretaceous (late Barremianearly Aptian).

S p e c i f i c d i a g n o s i s. Seeds tiny, broadly obovate in lateral view and almost circular in transverse section with an uneven surface of the endotesta formed from numerous longitudinal ridges separated by shallow depressions. Endotesta comprised of a single layer of palisade-shaped cells with densely spaced crystals and fibrous infillings.

D i s t i n g u i s h i n g f e a t u r e s. Kvacekispermum costatum is distinguished from Kvacekispermum rugosum E.M.FRIIS, P.R.CRANE et K.R.PEDERSEN described from the Catefica locality ( Friis et al. 2018c) by its much smaller and tangential longitudinal (f; SRXTM orthoslice yz0246) sections showing the amorphous fruit wall with prominent cavities formed by the scattered oil bodies (f); note the crystalliferous cells of the endotesta with endoreticulate infillings and outlines of small crystals (e); g) Longitudinal section (SRXTM orthoslice yz0490) showing the small poorly developed embryo surrounded by the crystalliferous cells of the endotesta; h, i) Probable seeds of Canrightia in lateral view showing the rounded point of attachment (above) and the pointed micropylar region (below); j) Crystalliferous cells of the endotesta showing crystals of two distinct sizes. Specimens, TV38-S164100 (holotype; a–g), TV43-S170069 (h), TV43-S170068 (i, j). Scale bars 300 Μm (a–d, h, i), 100 Μm (e–g), 20 Μm (j).

size (about half the length of K. rugosum ) and by the more numerous longitudinal ridges (about 35 ridges in K. costatum and about 20 in K. rugosum ). Seeds of Kvacekispermum are distinguished from seeds of Canrightiopsis E.M.FRIIS, G.W.GRIMM, M.M.MENDES et K.R.PEDERSEN ( Friis et al. 2015b) by their strongly ribbed seed surface.

D i m e n s i o n s. Length of seed: 0.6 mm; width of seeds: 0.4–0.5 mm.

D e s c r i p t i o n a n d r e m a r k s. Remains of the apical part of the fruit show a sessile rounded stigmatic area ( Text-fig. 19a, b ). There are no remains of hypanthium or other parts of the flower. The seeds are very small, elliptical to ovoid with pointed micropylar region. Both seeds were studied using SRXTM, but they are lignitised, strongly compressed and with an almost homogenized seed coat. Cellular details are best observed on the outer surface which shows crystal cells with equiaxial facets ( Text-fig. 19c ) very similar to the endotestal cells of Kvacekispermum rugosum as well as those of other Early Cretaceous chloranthoids. The surface of the endotesta is characterized by about 35 densely-spaced, rounded longitudinal ridges that extend from base to apex, and densely-spaced shallow and rounded depressions between the ridges ( Text-fig. 19a–c ).

A f f i n i t y a n d o t h e r o c c u r r e n c e s. Like Kvacekispermum rugosum , K. costatum is an extinct species closely related to the clade comprising extant Ascarina , Chloranthus and Sarcandra , among extant Chloranthaceae ( Friis et al. 2018c) . Kvacekispermum costatum is currently known only from the Torres Vedras locality, whereas K. rugosum is known only from the Vale de Água locality.

Figures

Text-fig. 19. Scanning electron microscope (SEM; d, e) and synchrotron radiation X-ray tomographic microscopy (SRXTM; a–c) images of a seed of Kvacekispermum costatum sp. nov. (a–c) and Kvacekispermum sp. (d, e); Torres Vedras locality, Portugal. a, b) Isolated, abraded seeds showing densely spaced longitudinal ridges; c) Detail of abraded seed in (b) showing surface of endotesta with imprints of crystals; d) Isolated, abraded seed showing longitudinal ridges; e) Abraded seed surface showing surface of endotesta with imprints of crystals. Specimens, TV44-S174098 (holotype; a), TV38-S174099 (b, c), TV43-S174612 (d, e). Scale bars 300 Μm (a, b, d), 50 Μm (c, e).