Verruca gailgoedertae Perreault & Buckeridge, 2019

Perreault, Ray T. & Buckeridge, John S., 2019, Paleogene Verrucidae (Cirripedia: Verrucomorpha) of North America, with descriptions of three new species, Zootaxa 4712 (1), pp. 34-50 : 34-50

Verruca gailgoedertae Perreault & Buckeridge sp. nov.

( Plate 1 , figs a–l)

urn:lsid:zoobank.org:act:D313492D-00E1-4A32-B048-4E7327A3224A

Diagnosis. Shell with moderately rugose, irregular external ribbing crossed by fine growth lines; all plates perforated by fine punctae; first and second articulating ribs on movable tergum similar in width; rostrum and carina articulating with up to five ribs; fixed scutal radio-alar wing extending out a distance equal to basal width of fixed scutum.

Type material.

Holotype. LACMIP 14759, a movable tergum (pl. 1, figs g, h).

Paratypes. NMV P332716 , a carina (pl. 1, figs a, b) ; NMV P332717 , a fixed tergum (pl. 1, figs i, j) ; NMV P332718 , a fixed scutum (pl. 1, figs e, f) ; NMV P332719 , a rostrum (pl. 1, figs c, d) .

Type locality. LACMIP locality 16851.

Stratigraphic range. Basal middle Eocene (Lutetian).

Distribution. Crescent/McIntosh transitional zone, Doty Hills, Washington, USA.

Additional material. 25 loose plates, including carinae, rostra, movable and fixed terga, fixed scuta; most plates are incomplete.

Description. Wall plates with exterior having moderately rugose longitudinal ribbing crossed by irregular, fine growth lines; all plates perforated by fine punctae. Carina highly asymmetrical, with strong tilt to fixed side; fixed tergal margin with two to three articular ribs, very short, indistinct; rostral margin with four to five articular ribs, top two long, lower very short, smooth; interior with prominent dependent sheath widest at apex of plate.

Rostrum rounded, fixed scutal margin with two very short, indistinct articular ribs; carinal margin with four ribs, long; ornamented by growth ridges and vague radial ridges; interior with very short sheath, dependent full length; interior otherwise featureless.

Fixed scutum convex, elongated horizontally; fixed tergal margin convex, without ribs; articular wing very long, triangular, separated from plate by wide sulcus, sharply edged on plate; upper margin of wing slightly concave; up to three articular ribs below wing; ornamented by regularly spaced growth lines on wing only, and by low radial ribs, especially on basal portions of plate; interior concave, with bordering ridge on wing; adductor plate high, erect, apical part highest, flat, with two ridges extending from corners to apex of plate; myophore absent.

Fixed tergum higher than wide, slightly bowed, plate flared slightly basally; fixed scutal margin flat, ala nonprotuberant, with indentation below; carinal margin with protruding ala extending from umbo, with indentation separating ala from four vague articular ribs below; apical margin slightly concave, umbo removed from apex; exterior ornamented by low, fine radial ridges, especially basally; interior very concave, apical shelf nearly horizontal, wide, dependent.

Movable scutum slightly convex, moderately curved tergally; apico-basal ridge very narrow, protruding; first articular rib extending to level of basi-occludent angle, nearly as wide as fixed scutal section; second articular rib centrally placed, protruding by its own width, sharply pointed; occludent margin strongly and smoothly convex; ornamented by regularly spaced, fine growth lines; interior with two small teeth present on movable tergal margin; movable tergal margin with internal growth lines.

Movable tergum slightly wider than high, flat to slightly bowed; apico-basal ridge curved slightly toward carinal margin, flat, with slightly overhanging margins, merging into plate near apex, growth lines straight, perpendicular to carinal margin; carinal portion triangular, fixed tergal margin convex, ornamented by fine regularly spaced growth lines and two to three faint radial incised lines; first articular ridge short, nearly width of second, with smooth area between ridge and second articular ridge; movable scutal margin indented at point of contact with smooth area; interior concave, with thickened occludent surfaces, bearing faint growth ridges, and shallow furrow coinciding with apico-basal ridge in lower half of plate.

Discussion. Verruca gailgoedertae sp. nov. may be distinguished from most other congeners by its strong rugose ribbing. The presence of punctae presently distinguishes it from V. alabamensis sp. nov., V. sauria and V. punica Buckeridge & Jagt, 2008 . It can be distinguished from V. sorrellae sp. nov. by its movable tergum, which has equal width first and second ribs: the shell would have been more depressed than V. rocana and V. digitali , and is more circular in outline than V. punica . Although similar in size to V. tasmanica and V. nuciformis Buckeridge, 1983 , it has more than twice the number of interlocking ribs between the carina and rostrum.

On the basis of its lack of abrasion, this species is interpreted as having lived in quieter sublittoral environments. The type locality is interpreted as bathyal with introductions from shallower waters ( Squires & Goedert, 1995) up to intertidal, and is thus a thanatocoenosis. The other two localities are interpreted as shallow shelf environments less disturbed than the type locality.

Etymology. Named in honor of the late Gail Goedert, wife of James Goedert, who together discovered this and many other fossil localities, and aided Washington paleontology immensely.

Type Repositories. Holotype LACMIP 14759 held by the Natural History Museum of Los Angeles County, CA; paratypes NMV P332716-9 held by Museum Victoria, Melbourne, Australia.

Figures

PLATE 1. Verruca gailgoedertae, sp. nov. a. Paratype NMV P332716, carina (exterior); b. paratype NMV P332716, carina (interior); c. paratype NMV P332719, rostrum (exterior); d. paratype NMV P332719, rostrum (interior); e. paratype NMV P332718, fixed scutum (exterior); f. paratype NMV P332718, fixed scutum (interior); g. holotype LACMIP 14759, movable tergum (exterior); h. holotype LACMIP 14759, movable tergum (interior); i. paratype NMV P332717, fixed tergum (exterior); j. paratype NMV P332717, fixed tergum (interior); k. paratype, fixed scutum (exterior); l. paratype fixed scutum (interior). All specimens are from the Lower Middle Eocene Crescent-McIntosh transitional zone, Location (CSUN 1573), Doty Hills, Washington, USA.