Litholepas klausreschi Nagler, Haug, Glenner, and Buckeridge, 2017

Gale, Andy S., Little, Crispin T. S., Johnson, Joel E. & Giosan, Liviu, 2020, A new neolepadid cirripede from a Pleistocene cold seep, Krishna-Godavari Basin, offshore India, Acta Palaeontologica Polonica 65 (2), pp. 351-362 : 353-354

Litholepas klausreschi Nagler, Haug, Glenner, and Buckeridge, 2017

Fig. 2D .

Material.—SMNS 70388/5; 13 individuals attached to a sponge, lower Tithonian (Jurassic), Solnhofen Limestone, Eichstätt, Germany.

Remarks.—This species is based upon 13 small (capitular length approximately 5 mm) specimens, attached to a sponge, from the Solnhofen Limestone of Eichstätt, Germany ( Nagler et al. 2017). I am unable to agree with their published interpretation that an upper latus is present on the specimens, and it appears that the colourised regions marked “l” in their figures (e.g., Nagler et al. 2017: fig. 5B, reproduced here as Fig. 2D 2 ) do not mark a distinct plate. I have therefore reconstructed the species without an upper latus ( Fig. 2D 1 ). The large number of growth-lines on the specimens can be taken as evidence that the individuals are fully grown.

The sculpture of the plates is cancellate, composed of very fine radial ribs which intersect with prominent growth lines and is similar to that found in zeugmatolepadids such as Concinnalepas ( Fig. 2E ). The shape of the terga and scuta are also similar to those of Concinnalepas (tergal apex inclined ventrally, gently convex carinal margins, rostral and basitergal angles of scuta nearly 90°). The genus is therefore tentatively interpreted as a paedomorphic zeugmatolepadid, in parallel with the titanolepadid genus Ivolepas Gale in Gale and Sorensen, 2015 and the scalpellid Virgilepas Gale, 2020 . In these genera, lateral plates are absent, probably as a consequence of precocious (accelerated) development.

Stratigraphic and geographic range.—Lower Tithonian, southern Germany.

Figures

Fig. 2. Fossil taxa assigned to Neolepadidae. A, B.?Neolepas augurata Buckeridge and Grant-Mackie, 1885 (original of Buckeridge and Grant-Mackie 1985: figs. 2, 3); Sinemurian–Pliensbachian (Lower Jurassic), New Caledonia. A. University of Auckland Geology Department UoA A291a, b, external mould of tergum. B. University of Auckland Geology Department UoA A292a, b, external mould of scutum. This is here tentatively interpreted as an eolepadid. C. Toarcolepas mutans Gale and Schweigert, 2015 (SMNS 26029); Toarcian (Jurassic), Harpoceras falciferum Zone, Zell u. Aichelberg, Germany; reconstruction based upon type material (Gale and Schweigert 2015: fig. 5). D. Litholepas klausreschi Nagler, Haug, Glenner, and Buckeridge, 2017; Tithonian (Upper Jurassic), Hybernoticeras hybernotum Zone, Eichstatt, Germany; D2, SMNS 70388/5 (decolourised original of Nagler et al. 2017: fig. 5B). I am unable to identify the upper latus, marked “l” in their figure; D1, reconstruction (mirrored for comparison with C). E. Concinnalepas costata (Withers, 1928) (NHMUK IC 1103); Kimmeridge Clay, 2 m beneath Freshwater Stone Band, Pectinatites pectinatus Zone, Tithonian (Upper Jurassic), Kimmeridge, Dorset, UK; fragmentary capitulum, showing scutum, tergum, and two lateral plates (based on original of Gale 2014: fig. 6l).Abbreviations: c, carina; l, upper latus; p, peduncle; r, rostrum; s, scutum;; t, tergum.

Fig. 1. NGHP-01 core sites (circles) and logging sites (stars) in the offshore Krishna-Godavari Basin, modified from Lorenson and Collett (2018). Site 12 is co-located with sites 10 and 21 (red circle). Inset shows the study area in Krishna-Godavari Basin is located on the eastern margin of peninsular India in the western Bay of Bengal.