Weltrichia fabrei Saporta, 1891

Moreau, Jean-David & Thévenard, Frédéric, 2018, Rediscovery of the allegedly “ destroyed ” holotype of Weltrichia fabrei Saporta, 1891 from the Rhaetian? / Hettangian of Lozère (Southern France), Geodiversitas 40 (21), pp. 521-527 : 524-526

Weltrichia fabrei Saporta, 1891

( Fig. 3 )

Weltrichia fabrei Saporta, 1891: 204 .

Williamsonia fabrei – Schuster 1911: 28.

HOLOTYPE. — M486 _2008.0.24_1 (Musée du Gévaudan, Mende,

Lozère, France). TYPE LOCALITY. — Chirac, Lozère, France (see Roquefort 1934;

Thévenard 1992).

STRATIGRAPHIC POSITION. — Detrital sandstones-variegated mudstones Formation composing the lowermost Mesozoic deposits of the Causses Basin.

AGE. — Rhaetian?/Hettangian.

ORIGINAL DIAGNOSIS. — Saporta 1891.

EMENDED DIAGNOSIS. — Large open urn-shaped reproductive structure. Central cup with one whorl of at least seven, slender and elongated sporophylls. Sporophylls curved inward apically. Margin of sporophylls entire. Sporophylls with a dorsal median ridge, an acute apex and a thick substance. Parallel vein-like furrows along the entire length of sporophylls and converging toward the apex. Distally, adaxial surface of sporophylls bears up to seven, elongated, tips forming branched structures.

DESCRIPTION

The specimen consists of a large open urn-shaped structure with a deep cup showing a low number of radially disposed sporophylls (rays). Upward, the cup is only partially open, up to 6.3 cm high and up to 5.3 cm wide. The cup is narrower at the base (2.4 cm wide) and the apex (3.3 cm wide). The cup consists of one whorl of more than seven slender, elongated and curved sporophylls ( Fig. 3 A-C). The sporophylls form an angle of up to 45° with the main axis of fructification. As the base, the specimen is broken, it is not clear if the sporophylls are fused or not ( Fig. 3 A-C). The upper parts of sporophylls are totally free and curve inward into the cup. The sporophylls are 42-60 mm long and 3-10 mm wide ( Fig. 3D, E ). Although apices of sporophylls are sometime missing, when preserved, they are acute. Margin of sporophylls seems entire. The sporophylls have a dorsal median ridge well-visible on the adaxial surface ( Fig. 3D, E ). Parallel vein-like furrows converging toward the apex are present along the entire length of the sporophylls. Substance of sporophylls are rather thick. At the apex, adaxial sporophyll surface bears up to seven, elongated, up to 6.5 mm long and 2.5 mm wide tips forming branched structures ( Fig. 3 A-E). Tips form an angle of up to 90° with the sporophyll axis.

COMPARISONS WITH OTHER SPECIES

Late Triassic and Early Jurassic Weltrichia species were reported from diverse countries such as Austria, France, Germany and Romania (e.g. Braun 1849; Saporta 1891; Krasser 1919; Popa 2001, 2014). The order of size of W.fabrei is comparable to that recorded of W.mirabilis from the Hettangian of Germany ( Braun 1849), whereas it is smaller than that of most species described in the Sinemurian of Romania (e.g. W. alfredii Krasser emend. Popa, 2014 ; W. antonii Popa, 2014 ; W. sol T.M. Harris, 1969 ; W. spectabilis (Nath.) T.M. Harris, 1969 ; and W. steierdorfensis Popa, 2014 ).Similarly to W. fabrei , a small number of sporophylls per cup (less than 20)is also reported for many Weltrichia species , such as W. alpina Krasser, 1919 from the Triassic of Germany ( Krasser 1919), W. mirabilis from the Hettangian of Germany ( Braun 1849), W. alfredii , W. antonii , W. johannae Popa, 2014 , and W. steierdorfensis from the Sinemurian of Romania ( Popa 2014).An elongated shape of rays is known among some species such as W. johannae , whereas the shape of W. fabrei rays clearly differs, with short-triangular sporophylls, like other species such as W. antonii and W. steierdorfensis ( Popa 2014) . This shape also differs from that of W. mirabilis sporophylls, which are wider and show a short free apical part (see Saporta 1891; Schuster 1911). Similarly to W. fabrei a central ridge/costa is recorded on rays of W. alfredii , W. mirabilis and W. steierdorfensis ( Braun 1849; Popa 2014). By W. fabrei as by most Weltrichia species the sporophylls are leathery ( Popa 2001, 2014).

Figures

FIG. 3. — A-E, Weltrichia fabrei Saporta, 1891, holotype; A-C, open urn-shaped cup showing one whorl of seven, elongated and curved sporophylls bearing branched structures; photograph (A), 3D photogrametric surface reconstruction highlighting weakly visible details (B), interpretative sketch (C); D-E, enlargement of sporophylls; photograph (A), 3D photogrametric surface reconstruction highlighting weakly visible details (B). Abbreviations: Br., elongated tips forming branched structures; Ri., dorsal median ridge; Sp., sporophylls. Scale bars: A-C, 5 cm; D-E, 2.5 cm.