Eoverruca hewitti Withers 1935
Creators: name: Jagt, John W. M.
name: Jaskuła, Iwona
name: Witek, Anna
name: Jagt-Yazykova, Elena A.
Publisher: name: Zenodo
Year: 2008
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Maxillopoda
Sessilia
Proverrucidae
Eoverruca
Eoverruca hewitti

description: Eoverruca hewitti Withers, 1935
(Figs 2, 3)
Original description. Eoverruca hewitti Withers, 1935: 338, text-figs 37, 38; pl. 44, figs 9–18.
Types. The holotype (NHM In. 27598) is a fixed scutum (Withers, 1935: pl. 44, fig. 9a, b), 1.7 mm in length, from the upper Santonian (Uintacrinus socialis Zone) of East Harling, Norfolk, eastern England. Withers (1935) had a total of 64 valves; all of these are contained in the collections of the Natural History Museum, Department of Palaeontology (London), under registration numbers NHM In. 27280-27281, In. 27595-27607 and In. 27725-27748.
Material examined. NHMM 2006 024/1-30, comprising carinae, a single rostrum, movable and fixed scuta, movable terga, a single fixed?tergum as well as lateral valves; all from samples 3, 4A, 4B and 5 taken at the JeŻówka section (Fig. 1 C; Table 1).
Description. Valves with transverse ridges sharp-edged, prominent, somewhat overhanging, and undulating on rostrum and carina; a few longitudinal ridges are seen on rostrum and carina; transverse ridges project as sharp points on outer margins of valves.
Carina (Fig. 2 G, I) small (0.95–1.0 mm in length), semi-cylindrical, slightly asymmetric; length c. 1.5 times width (but damaged); barely bowed inwards; transversely strongly convex and well rounded; ornament of prominent, smooth transverse ridges (at least nine, as preserved), of varying width and narrow, step-like, occasionally undulating interspaces; basal margin irregular (but damaged), concave, and faintly produced laterally below every transverse ridge; apical portion damaged, but estimated to have projected freely to c. onethird the length from apex; basal portion concave.
Rostrum (Fig. 2 H) small (0.85 mm in length, 0.7 in width, as preserved), semi-conical; basal margin irregular (but damaged); barely bowed inwards; transversely strongly convex to semi-carinate; estimated to have projected freely to c. half its length from apex; ornament as in carina, less well marked, with interspaces more or less flush with transverse ridges in single specimen available.
Fixed scutum (Fig. 2 J) small (1.15 mm in length, 1.05 mm in width as preserved), triangular (but damaged), faintly curved on tergal side, faintly convex transversely; apico-basal ridge slightly raised, flat-topped, widening markedly towards basal margin, near-equal in width to occludent side of valve; tergal side obliquely inclined inwards, narrow, with two articular ribs; ornament of transverse ridges, projecting beyond both occludent and tergal margins, straight to undulating, with interspaces either narrow or of equal width; occludent side with additional longitudinal striation radiating from apical portion towards basal margin; striae more or less of similar strength. Inner side abraded, but apical portion estimated to have projected freely to c. one-third of length of valve.
Movable scutum (Fig. 2 D) small (1.3 mm in length), narrower than fixed scutum; apico-basal ridge also narrower, prominently raised and of near-equal width towards basi-tergal angle; prominent growth ridges not downturned on occludent margin; ornament of transverse ridges, straight to slightly undulating, with longitudinal striation on occludent side, similar, more subdued, to that of fixed scutum (Fig. 2 J); prominent premordial valve with irregular basal margin in one specimen (Fig. 2 D, NHMM 2006 024/4), reminiscent of the one seen in Vulcanolepas osheai (see Buckeridge, 2000: fig. 4F, G; Southward & Jones, 2003; Yamaguchi et al., 2004).
Fixed?tergum (Fig. 2 E) small (0.95 mm in length, damaged), subrhomboidal, faintly convex transversely; apico-basal ridge narrow, raised, produced at basal margin; ornament of transverse ridges, undulating and projecting laterally; scutal side damaged, leaving no trace of articular ribs.
Movable tergum (Fig. 2 A–C) small (between 1.4 and 1.8 mm in length), elongate; apico-basal ridge central, fairly narrow, increasing in width towards basal angle, of regular curvature; carinal margins of equal length, forming c. 70 degrees angle; occludent margin concave, shorter than scutal margin; two articular ribs on scutal side, one prominent and extending from apex to middle of scutal; depression on scutal side of this, separating it from rounded occludent margin forming second rib; ornament of transverse ridges, straight, produced markedly along upper carinal margin, more or less subdued between articular ribs on scutal side.
Lateral valves (Figs. 2 F, 3A–F) small, with thin edges (overall width between 0.9 and 1 mm), of varying height, and of two types; one with basal angle positioned near-centrally and, on inner surface, c. one-third of valve height marked with few, prominent growth lines; the other with basal angle close to one side and more than upper half with such lines; ornament of pronouced transverse ridges and (sub)central ridge, similar to other valves.
description: Published as part of Jagt, John W. M., Jaskuła, Iwona, Witek, Anna & Jagt-Yazykova, Elena A., 2008, A new record of the Late Cretaceous cirripede Eoverruca hewitti (Verrucomorpha, Proverrucidae) from southern Poland, pp. 59-68 in Zootaxa 1671 on pages 62-64, DOI: 10.5281/zenodo.180203