Atlantocarpus sp.

Friis, Else Marie, Crane, Peter R. & Pedersen, Kaj Raunsgaard, 2020, Multiparted, Apocarpous Flowers From The Early Cretaceous Of Eastern North America And Portugal, Fossil Imprint 76 (2), pp. 279-296 : 287-289

Atlantocarpus sp.

Text-fig. 5e, f

1997 Cone-like structure associated with Anacostia at the Buarcos locality; Friis et al., fig. 10.

D e s c r i p t i o n a n d r e m a r k s. A single, multicarpellate floral structure from the Buarcos locality, Portugal (S105025, Buarcos sample 244), closely resembles Atlantocarpus virginiensis from the Puddledock locality.

The specimen is about 1.9 mm long, 3.2 mm long including the long stalk ( Text-fig. 5e ). As in A. virginiensis the floral structure is preserved at an early developmental stage and internal features are not known for this specimen. The remains of tepals are bent over the basal part of the receptacle at the level of the collar obscuring any stamens, if they were present.

The floral receptacle is elongate conical ( Text-fig. 5e, f ) and the gynoecium is apocarpous consisting of about 40 spirally arranged carpels. The carpels are slightly flattened laterally and slightly swollen at the apex, probably reflecting an expanded stigmatic region. As in Atlantocarpus virginiensis , this distal portion of the carpels sometimes appears grooved and indistinctly bifid ( Text-fig. 5f ). The Buarcos fossil closely resembles Atlantocarpus virginiensis from the Puddledock flora and differs mainly in the number of carpels: about 50 in Atlantocarpus virginiensis and about 40 in Atlantocarpus sp. The specimen is not sufficiently distinctive to be assigned to a new species, and we assign it to the same genus as Atlantocarpus sp.

Another possibly related fossil from the Vale de Água locality (S101300, Vale de Água sample 141) consists of an elongated receptacle with about 40 spirally arranged scars, probably from abraded or shed carpels ( Text-fig. 5g ). The pedicellate structure is very similar in shape to Atlantocarpus sp. from Buarcos, but larger, about 2.5 mm long without the stalk, and may represent a later developmental stage of an Atlantocarpus -like flower. It is here referred to as Atlantocarpus ? sp.

Figures

Text-fig. 5. Scanning electron micrographs (d–g) and synchrotron radiation X-ray tomographic microscopy orthoslices (a–c) of flowers of Atlantocarpus virginiensis gen. et sp. nov. (a–d: holotype, PP43780, Puddledock sample 156), Atlantocarpus sp. from the Early Cretaceous Buarcos locality (e, f: S105025, Buarcos sample 244) and receptacle of Atlantocarpus? from the Early Cretaceous Vale de Água locality (g: S101300, Vale de Água sample 141). a) Flower in lateral view showing scar from a single bract (br), attachment scars of tepals (t) and stamens (st) on the expanded basal portion of elongated receptacle and young carpels; b) Flower in lateral view showing expanded basal portion of the elongated receptacle and young carpels; c) Flower in longitudinal section showing expanded basal portion of the elongated receptacle and young carpels; note the irregular, possibly expanded stigmatic region (arrow heads), (orthoslice yz0340); d) Flower in lateral view showing attachment scars of tepals (t) and stamens (st) on the expanded basal portion of elongated receptacle and young carpels with possible grooved stigmatic regions (arrow heads); e) Flower in lateralview showing expandedbasal portion ofelongated receptacle and young carpels; f) Detail of flower in(e) showing