Brachylepas, WOODWARD, 1901

Kočí, Tomáš, Veselská, Martina Kočová & Jagt, John W. M., 2014, Barnacles (Crustacea, Cirripedia, Thoracica) From The Bohemian Cretaceous Basin Described By Fritsch And Kafka (1887), With The Exclusion Of The Family Stramentidae, Acta Musei Nationalis Pragae Series B (Acta Mus. Nat. Prag.) 70 (3 - 4), pp. 223-234 : 227-228

Brachylepas fallax ( DARWIN, 1851)

Pl. 3, figs. 1a–m, 2a–g; Pl. 4, figs. 1–8

1851 Pollicipes fallax DARWIN, p. 75, pl. 4, fig. 8a, b. 1885 Pollicipes fallax DARWIN: Kafka, p. 19, pl. 3, figs.

2r (non fig. 2l), 3a, b (non fig. 3sl, l´). 1887 Pollicipes fallax DARWIN: Fritsch and Kafka, p. 10,

fig. 17 (non l´, sl). 1893 Pollicipes fallax DARWIN: Fritsch, p. 309. 1935 Brachylepas fallax (DARWIN): Withers, p. 367, pl.

48, figs. 1–24.

M a t e r i a l. Specimens from Uhřetická Lhota are as follows: a right scutum (NM O4023; the original from Fritsch and Kafka, 1887, fig. 17b (s), collected by J. J. Jahn), a rostrum (NM O4024; the original from Fritsch and Kafka, 1887, fig. 17r); a right scutum (NM O4025); a left scutum (NM O4026). Lot NM O4093 comprises a right tergum and four lower latera, the originals from Fritsch and Kafka, 1887, fig. 17. Lot NM-ČL6989 (nos 387, 388, 390) represents the originals from Fritsch and Kafka (1887, fig. 17t, t, c), while lot NM-ČL6990 (no. 879) comprises a scutum, a rostrum and a carina. Specimen NM-ČL6992 (Os 292), from Choceň (Sutiny), is also the original from Kafka (1885, pl. 3, 2 r).

D e s c r i p t i o n. Carina semiconical, slightly bowed inwards, strongly convex transversely, yet not carinate; basal margin slightly concave; outer surface with a number of strong distinct flattened transverse ridges, regularly spaced; longitudinal ornamentation of very fine distinct longitudinal lines, preserved only in NM-ČL6989 (no. 390). The carina from Úhřetická Lhota measures 5.85 mm in length, while NM-ČL6989 (no. 390), which lacks the apex, measures 5 mm in length and 2.35 mm in basal width. NM-ČL6992 (Os 292), from Choceň (Sutiny), measures 5.6 mm in length and 2.6 mm in basal width. Rostrum semiconical, wider than carina, bowed inwards and strongly convex transversely; transverse ornamentation resembles that of the carina, but less pronounced. Distinct longitudinal apicobasal ridge developed. NM-ČL6990 measures c. 6 mm in length and c. 4.64 mm in basal width. Measurements (estimated because matrix partially covered) of NM O4024 are: length c. 4.5 mm and width c. 7 mm. Scutum elongated triangular in outline, moderately convex transversely. Rounded, strongly convex occludent margin with acuminate apex. Apex strongly bowed towards tergum. Tergo-lateral margin slightly concave, mainly in upper part, near apex. Edge of basilateral margin protruding sharply; basilateral angle 100° (NM O4025); basal margin almost straight. Rostral angle 130° (NM O4025). Apicobasal ridge significantly pronounced, broad and curved convexly. Broad apicobasal ridge in NM O4026 measuring 0.45 mm in width. Transverse ridges significantly pronounced, equally spaced and thickened at occludent margin, narrowing near upper part of tergal margin. Overall length of right scutum NM O4023 c. 5 mm, basal width 3.4 mm, that of another right scutum, NM O4025, c. 6.4 mm, basal width 5 mm. Left scutum (NM O4026) c. 5.9 mm, basal width 3.7 mm. Tergum (NM-ČL6989, no. 388) subrhomboidal in outline, moderately convex transversely with prominent broad apicobasal ridge, curved towards carino-lateral margin and concave towards occludent and scutal margin. Apex acuminate, slightly bowed inwards towards occludent margin. In upper third of valve a distinct sharp concave apico-scutal ridge, parallel to apicobasal ridge. Transverse ridges prominent and equally spaced, as in scutum. Longitudinal ornamentation consisting of very fine lines. Basal angle between lateral and scutal margin 70°. Carinal angle between lateral and carinal margin 60°. Overall length 5.95 mm.

R e m a r k s. Brachylepas has carinae, rostra, scuta, terga and upper latera that closely resemble those of Pycnolepas WITHERS, 1914 . In fact, Withers (1914) included B. fallax in Pycnolepas . However, the latter can be differentiated by the more prominent transverse and longitudinal ridges on the carina, rostrum and upper latus, with the exception of B. naissanti (HÉBERT, 1855), which has lower L/W ratios, a semicircular basal outline and thickened inner margine ( Jagt, 2007). The scutum of Pycnolepas is more elongate and the apex more acute. Brachylepas naissanti has a wide semi-conical carina and rostrum with significantly raised longitudinal ribs. The terga and scuta of B. naissanti have less prominent transverse sculpture than B. fallax. The imbricating plates of the latter lack longitudinal ribs and differ from those of B. naissanti in being more rounded at the apex. The longitudinal ribs of the imbricating plates of B. fallax are developed as furrows. Brachylepas guascoi (BOSQUET, 1857) has a wider carina with more prominent transverse ridges, a scutum with very pronounced transverse ridges and tergum with a straight apicobasal ridge nearer the scutal margin than in B. fallax. More details on the relationships between species of Brachylepas can be found in Jagt (2007). Brachylepas nervosa ALEKSEEV, 2009, from the upper Lower Maastrichtian of Crimea ( Ukraine) has a straighter carina and rostrum and the ridge on the scutum divides the valve into two unequal parts. Alekseev (2009, p. 34) considered some western European records of B. fallax to pertain to B. nervosa.

O c c u r r e n c e (B C B). Upper Turonian – Lower

Coniacian (Úhřetická Lhota, Choceň (Sutiny).

O v e r a l l r a n g e. Upper Turonian – uppermost Maastrichtian.