Arcoscalpellum, HOEK, 1907

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 : 226

Arcoscalpellum angustatum ( GEINITZ, 1843)

Pl. 2, fig. 4

*1843 Pollicipes angustatus GEINITZ, p. 7, pl. 4, fig. 10.

1885 Scalpellum quadratum DARWIN: Kafka, pl. 1, fig. 1d.

1887 Scalpellum quadratum, DARWIN: Fritsch and Kafka, p. 5, fig. 3a-d.

1887 Scalpellum quadricarinatum REUSS: Fritsch and Kafka, p. 5, fig. 4a-c.

1887 Scalpellum kamajkense KAFKA: Fritsch and Kafka, p. 5, fig. 5a, b.

1887 Scalpellum fossula DARWIN: Fritsch and Kafka, p. 5, fig. 6a, b.

1887 Scalpellum maximum SOWERBY sp.: Fritsch and Kafka, p. 6, fig. 7c (non 7a, b).

1887 Scalpellum angustum DIXON sp.: Fritsch and Kafka, p. 6, fig. 8a-d.

1887 Scalpellum crassum KAFKA: Fritsch and Kafka, p. 7, fig. 10.

1887 Pollicipes elongatus STEENSTRUP: Fritsch and Kafka, p. 11, fig. 20a, b.

1889 Scalpellum angustatum DIXON: Fritsch, pp. 95, 96, fig. 120.

1893 Scalpellum quadratum DARWIN: Fritsch, pp. 108, 109, fig. 142.

1935 Scalpellum (Arcoscalpellum) angustatum (GEINITZ): Withers, p. 215, pl. 25, figs. 2–20; pl. 26, fig. 1.

M a t e r i a l. A single left scutum only (NM O 4021) survives from Fritsch and Kafka‘s (1887) original collection; it measures 7.7 mm in length and 4 mm in basal width.

D e s c r i p t i o n. Scutum trapezoidal, elongated; cross section slightly convex; length about twice the width; occludent margin straight or slightly curved and basal margin at right angles; edge of occludent margin bending inwards; basal margin slightly concave to straight; lateral margin extending to about two-thirds of scutal height and tergal margin to one third of scutal height; apicobasal margin distinct and rounded; towards lateral and tergal margins, area of scutum slightly sloping; lateral margin convex; tergolateral angle distinct.

R e m a r k s. The present species resembles A. fossula ( DARWIN, 1851), but differs from it in the scutal construction (see also Collins in Viaud et al. 1983). Arcoscalpellum lineatum ( DARWIN, 1851), from the Upper Albian to?Lower Santonian of England, France and Germany, differs in having longitudinal lines on the carinal tectum, narrower terga and wider scuta. The scutum of A. maximum (J. DE C. SOWERBY, 1829) (see below) has a less pronounced apicobasal ridge and generally shows finer transverse and longitudinal ornamentation.

O c c u r r e n c e (B C B). Upper Cenomanian (Předboj, Černovičky [recorded by Žítt et al., 1999, p. 112, as Scalpellum sp. ); Lower Turonian (Velim, Kamajka, Turkaňk, Kněžívka [recorded by Žítt et al., 1999, as Scalpellum crassum], Odolena Voda [recorded by Hradecká et al., 1994, p. 19, as Scalpellum crassum], Chrtníky [recorded by Žítt et al., 2006, unit 7, 8f as Scalpellid gen. et sp. indet.], Běstvina u Ronova nad Doubravou [recorded as Scalpellum sp. by Žítt and Nekvasilová, 1994, p. 26]; Middle Turonian (Všetaty); Upper Turonian (Úpohlavy, Novosedlice, Stradouň); Upper Turonian – Lower Coniacian (Lány na Důlku near Pardubice).

O v e r a l l r a n g e. Albian – Lower Santonian.