PBDB Taxon

Basic info	Taxonomic history	Classification	Included Taxa
Morphology	Ecology and taphonomy	External Literature Search	Age range and collections

Leptellina (Leptellina) llandeiloensis

Strophomenata - Strophomenida - Leptellinidae

Taxonomy

Leptaena llandeiloensis was named by Davidson (1883). Its type specimen is GSM 37538, a valve (dorsal valve internal mould), and it is a 3D body fossil.

It was recombined as Plectambonites llandeiloensis by Reed (1917); it was recombined as Leptelloidea llandeiloensis by Jones (1928); it was recombined as Leptellina llandeiloensis by Williams (1962), Candela and Harper (2009); it was recombined as Leptellina (Leptellina) llandeiloensis by Candela and Harper (2014).

Sister species lacking formal opinion data

L. elegantula

Year	Name and author
1883	Leptaena llandeiloensis Davidson p. 171 figs. pl. XII figs. 26, 26a, b, non figs. 27-29
1917	Plectambonites llandeiloensis Reed pp. 876 - 877 figs. pl. XIII figs. 32-34; pl. xiv, figs. 1-3.
1928	Leptelloidea llandeiloensis Jones p. 477
1962	Leptellina llandeiloensis Williams pp. 164 - 165 figs. P1. XV, figs. 27-29, 32
2009	Leptellina llandeiloensis Candela and Harper p. 262 figs. 6m, p
2014	Leptellina (Leptellina) llandeiloensis Candela and Harper pp. Supplement 1

Diagnosis

Reference	Diagnosis
F. R. C. Reed 1917	Shell transversely semielliptical, strongly concavo-convex, widest along hingeline ; cardinal angles rectangular; hinge-line minutely crenulated. Pedicle-valve strongly and uniformly convex, swollen, rounded; beak small, pointed, slightly incurved, scarcely projecting ; hinge-area narrow, in plane of valve. Brachial valve strongly concave, with more or less flattened disc ; hinge-area narrow, nearly at right angles to disc. Interior of pedicle-valve with low rounded concentric thickening of shell close to margin; teeth small, stout, triangular, widely separated; diductor muscles deeply sunk, well defined, short, triangular, strongly divergent, weakly bilobed by shallow notch on anterior margins, posteriorly embracing well-marked oval adductor scar ; pair of vascular trunks running forwards with slight divergence for about half length of valve from anterior inner angles of diductors, each trunk then dividing into a short inner and a long outer branch widely diverging and giving off short subparallel branches to margin. Interior of brachial valve with small bilobed (?) cardinal process, and thickened undefined cardinal plate giving off laterally a long curved somewhat undulating ridge on each side forming anterior walls of large transverse sockets for teeth; sharp prominent concentric thickened semicircular ridge situated at about half length of valve, bilobed and sharply indented in middle, bounding pair of large depressed concave areas separated by thin short median septum or ridge only developed in front and not continued back to cardinal plate ; adductors weakly impressed in these areas, flabelliform, divergent, extending about one-third length of shell. Interior of shell finely punctate in radial lines. External surface ornamented with 5-7 straight radiating primary radii regularly disposed (and occasionally shorter secondary radii), with fine radial striae between them.
A. Williams 1962	Variably coneavo-convex and semi-elliptical Leptellina with the pedicle valve slightly more than one-third as deep as long and three-fifths as long as wide; ornamentation finely parvicostellate with a modal count of 11 costellae per millimetre antero-medianly; concentric lamellae rarely and distantly developed; lophophore platform less than one-half as long as wide and averaging two-thirds the length of the brachial valve; ventral muscle-scar subtriangular, about one-quarter as long as the pedicle valve.