Paractinobalanus moronii Carriol, 2008, sp. nov.

Paractinobalanus moronii sp. nov.

Fig. 4 (1a–8b)

Diagnosis: As for the genus.

Etymology: The species is named for M. A. Moroni, in recognition of her work on cirripedes (particularly Balanus mylensis and Actinobalanus actinomorphus).

Occurrence: Ferrière-Larçon, Pauvrelay (Paulmy commune), Indre-et-Loire, France; faluns of Middle Miocene age.

Material: Holotype: MNHN A25760 carino-lateral. Paratypes: MNHN A25758 scutum; MNHN A25759 tergum; MNHN A25762 lateral; MNHN A25761 carina; MNHN A25764 rostrum; MNHN A25763 lateral with a fragment of basis, MNHN A27123 carino-lateral with a fragment of both carina and basis.

In addition to the type series, other numerous unregistered plates from the type localities are at my disposal.

Measurements: Holotype, MNHN A25760: height of middle of the plate 2.8 mm; paratype, MNHN A25758: basal margin 1.4 mm, occludent margin 2.1 mm, articular margin 1.85 mm; paratype, MNHN A25759: articular margin 1.9 mm; paratype, MNHN A25762: height of middle of the plate 1.4 mm, basal margin 1.7 mm; paratype, MNHN A25761: height of middle of the plate 2.7 mm; paratype, MNHN A25764: height of middle of the plate 2.55 mm.

Description: Shell small, white to pink, with six solid compartmental plates, conic to globular as suggested by shape of plates (no complete shell), parietes isosceles, exterior smooth, internal ribbing regular, well formed up to sheath; sheath without or with faint growth lines, occupying about one third length of compartment; radii solid with summits slightly oblique or parallel to basis, generally concave in their middle, sutural edges strongly septate; alae with summits inclinate, superior alar margin with secondary alar increment, inferior alar margin lacking. Scuta white often tinged with pink, often arched between apex and basal margin, longitudinally depressed between occludent margin and line delineating tergal segment; occludent margin very sinuous, tergal margin generally slightly convex; basal margin plicated at level of tergal segment; basitergal angle obtuse; exterior ornamented with growth ridges; interior with articular ridge long, not prominent, articular furrow long, narrow; adductor ridge absent, adductor pit shallow, near occludent margin; lateral depressor pit absent. Terga white often tinged with pink, flat; basal margin with carinal and scutal part concave; scutal margin straight or concave; carinal margin convex; exterior of plate ornamented with growth ridges crossed by faint longitudinal striae near carinal margin; spur broad, short, end rounded; spur furrow open (fasciole); distance from basiscutal angle to spur smaller than spur width; internally articular ridge not prominent, articular furrow long, shallow; crests for depressor muscle well marked.

FIGURE 4. Paractinobalanus moronii sp. nov., external and internal side of plates: 1a, b, scutum, paratype MNHN A25758; 2a, b, tergum, paratype MNHN A25759; 3a, b, carino-lateral, holotype MNHN A25760; 4a, b, carina, paratype MNHN A25761; 5a, b, lateral, paratype MNHN A25762; 6, lateral with a fragment of basis, paratype MNHN A25763; 7, right carino-lateral with a fragment of both carina and basis, paratype MNHN A27123; 8a, b, rostrum, paratype MNHN A25764.

Affinities: The capitular plates of this new species are very similar with those of Solidobalanus mylensis Moroni, 1967, but the porous basis distinguishes the species.