Campylopus lusitanicus HEDENÄS, BOMFLEUR et E.M. FRIIS, 2023

Bomfleur, Benjamin, Hedenäs, Lars, Friis, Else Marie, Crane, Peter R., Raunsgaard, Kaj, Pedersen, Mendes, Mário Miguel & Kvaček, Jiří, 2023, Fossil Mosses From The Early Cretaceous Catefica Mesofossil Flora, Portugal - A Window Into The Mesozoic History Of Bryophytes, Fossil Imprint 79 (2), pp. 103-125 : 112-114

Genus Campylopus BRID., 1818

Campylopus lusitanicus HEDENÄS, BOMFLEUR et E.M. FRIIS sp. nov.

Text-fig. 7e–h

H o l o t y p e. S266385 (Catefica sample 49; figured

Text-fig. 7e–h ).

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. PFN003150.

P a r a t y p e. S266383 (Catefica sample 49).

R e p o s i t o r y. Palaeobotanical Collections,

Department of Palaeobiology, Swedish Museum of Natural

History, Stockholm, Sweden.

E t y m o l o g y. The species epithet refers to the Latin name of Portugal where the fossils were discovered.

T y p e l o c a l i t y. Catefica (39° 03ʹ 30ʺ N, 09°14ʹ 30ʺ

W), between the villages of Catefica and Mugideira, about 4

km south of Torres Vedras, Portugal.

T y p e s t r a t u m a n d a g e. Almargem Formation,

Early Cretaceous (Aptian–early Albian).

S p e c i f i c d i a g n o s i s. A member of the genus

Campylopus , but with leaves that are much smaller than those of any extant species.

D i s t i n g u i s h i n g f e a t u r e s. The leaves of

Campylopus lusitanicus are up to 1.6 mm long, much smaller than the leaves of any extant species, which are at least 3 mm and up to ca. 10 mm long. Leaves have a very broad costa that occupies about half the leaf width at the base of the leaf and that fills out the acumen almost completely. Leaves have a well-developed epidermis on both the adaxial and abaxial sides, with one layer of large guide cells and multiple layers of abaxial stereids, but only a single layer of adaxial stereids.

D e s c r i p t i o n a n d C o m m e n t s o n t h e

M a t e r i a l. Specimens S266383 and S266385 are shoot fragments up to ca. 2.0 mm long (length of broken leaf apices estimated), with leaves that are up to 1.6 mm long. Leaves have a broad costa that occupies about half the leaf width in the basal leaf portion and most of the acumen ( Text-fig.

7e, f). The epidermis of the costa is well differentiated on both the adaxial and abaxial sides with enlarged epidermal cells ( Text-fig. 7g, h ). There is one layer of large guide cells, multiple layers of abaxial stereids, and a single layer of adaxial stereids ( Text-fig. 7g, h ). The acumen consists entirely of the costa; a lamina is lacking.

S y s t e m a t i c r e l a t i o n s h i p s. The fossil material is so similar to the extant Campylopus that it can be readily assigned to that genus. Campylopus , like Dicranodontium , is one of twelve genera of Leucobryaceae . Like in many extant

Campylopus species, our fossil has long and narrow leaves with a broad costa, but the leaves in the fossils are much smaller (Bonfim Santos and Stech 2017). As in the case of

Dicranodontium minutum we think it unlikely that the small leaf size of Campylopus lusitanicus reflects shrinkage during preservation. The epidermis is well differentiated on both abaxial and adaxial sides, with enlarged epidermal cells, one layer of large guide cells, multiple layers of abaxial stereids,

and a single layer of adaxial stereids (cf., Frahm 1997). The latter distinguishes Campylopus from Dicranodontium ,

including D. minutum described above, which has multiple layers of adaxial stereids. The acumen consists entirely of the costa and a lamina is entirely lacking.The costa in Campylopus is broader than in Microcampylopus (MÜLL. HAL.) M. FLEISCH.

It is also broader than in species of Campylopodium (MÜLL.

HAL.) BESCH. where the costa occupies about one third of the leaf base. The genus Campylopus is widely distributed globally (Stech and Wagner 2005).

Figures

Text-fig. 7. Synchrotron radiation X-ray tomographic microscopy (SRXTM) images (volume renderings, a, b, e, f; orthoslices, c, d, g, h) from shoots of Dicranodontium minutum HEDENÄS, BOMFLEUR et E.M.FRIIS (a–d) and Campylopus lusitanicus HEDENÄS, BOMFLEUR et E.M.FRIIS (e–h) from the Early Cretaceous Catefica mesofossil flora, Almargem Formation, Portugal. a, b: Shoot apices with several leaves showing the broad costa comprising almost the full width of the leaf. c, d: Transverse sections (orthoslices xy2925, xy1725) of leaves near the shoot apices showing the broad costa. Note the prominently expanded guide cells with several layers of stereids on both their dorsal and ventral sides, especially distinct in (c). e, f: Shoot apex with several leaves showing the broad costa. g, h: Transverse sections (orthoslices xy0867, xy1675) of leaves near the shoot apices showing the expanded guide cells with uniformly unistratose stereids on their ventral side. Specimens, D. minutum, Catefica 49-S266382 (a, c; holotype), Catefica 49-S266384(b, d); C. lusitanicus Catefica 49-S266385 (e–h; holotype). Scale bars = 1 mm (a, b, e, f), 100 µm (c, d, g, h).