Tarracospeum raveni incisum, Quiñonero-Salgado & López-Soriano & Alonso, 2024

Tarracospeum raveni incisum ssp. nov.

( Figs. 1 View FIGURE1 -3)

Type locality: Font del Mas, Vilaverd, Tarragona province, 31TCF 4726075938. 242 m altitude (Fig. 4).

Other localities: Font de la Ceba, Montblanc, Tarragona province, 31TCF 4561183381, 339 m altitude; Font de Llorach, Montblanc, Tarragona province, 31TCF 4712080032, 284m altitude.

Type material: Holotype RMNH.MOL.350852, Naturalis, 12 s in SQS coll . Paratypes: 1 s RMNH.MOL.350853 .

Other material examined: 10 shells of Tarracospeum raveni incisum from Font de la Ceba and 12 shells from Font de Llorach (Montblanc, Tarragona) (SQS leg.); 20

A B C D E

shells of Tarracospeum raveni raveni from the type locality; Font del Baró (Querol, Tarragona) and Font Massat (Santes Creus, Tarragona) (SQS leg.) .

Etymology: incisum (Latin = cut, incision, snip), referring to the incision in the base of the peristome.

Description: Small shell, fragile, translucid, with cylindrical to subcylindrical shape, 4 to 6 whorls, slightly convex, 1.69–2.24 mm high and 0.64–0.99mm wide. Marked sutures, slightly angulated in the last whorls. The microsculpture of the teleoconch shows irregular growth lines ( Fig. 1 View FIGURE1 B-D), while the protoconch surface is smooth or with only a faint rugosity ( Fig. 1C View FIGURE1 ). Clear separation between protoconch and teleoconch. No umbilicus. Last whorl ascendent

SH SW BWH PH PW

HOLOTYPE 2.16 0.84 1.23 0.69 0.59

min 1.86 0.71 1.05 0.53 0.47

Font del Mas

(ssp incisum) max 2.17 0.91 1.25 0.71 0.59

(n=6) mean 2.01 0.81 1.17 0.63 0.55

st.dev . 0.147 0.073 0.085 0.069 0.050

min 2.01 0.72 1.13 0.58 0.49

Font de

La Ceba max 2.37 0.85 1.27 0.71 0.59

(ssp incisum) mean 2.20 0.80 1.20 0.65 0.55

(n=10) st.dev . 0.132 0.043 0.055 0.042 0.029

min 1.69 0.64 0.96 0.50 0.45

Font de

Llorach max 2.44 0.99 1.35 0.74 0.68

(ssp incisum) mean 2.13 0.82 1.20 0.65 0.57

(n=12) st.dev . 0.281 0.135 0.139 0.092 0.077

min 1.75 0.66 1.06 0.55 0.50

Font del Baró max 2.61 1.11 1.51 0.85 0.73

(ssp raveni )

(n=8) mean 2.16 0.86 1.26 0.69 0.60 st.dev . 0.274 0.145 0.139 0.100 0.077

min 1.40 0.42 0.78 0.35 0.36

Font Massat max 2.18 0.91 1.25 0.68 0.62

(ssp raveni )

(n=12) mean 1.77 0.69 1.04 0.53 0.49 st.dev . 0.253 0.127 0.147 0.085 0.074 Mesures de les conquilles de TOrrOcospeum rOveni incisum ssp. nov. i TOrrOcospeum rOveni rOveni en comparació. SH; alçada de la conquilla; SW:amplada de la conquilla; PH: alçada de l’obertura; PW:diàmetre de l’obertura.

towards the aperture. Aperture showing minimum separation from the penultimate whorl, 0.49–0.74 mm in height and 0.44–0.68 mm in diameter, ovoid in shape, very prominent external curvature; in the upper side a slight angulation is observed, continued in the outer side with a more marked undulation if observed from the external side of the aperture; the base shows a semi-circular incision. Outer lip not thickened, but everted in its whole extension.

Dimensions: See Table 1 and Fig. 3.

Habitat: Stygobitic. Shells were washed out from their habitat, likely after a sudden rise of the subterranean water levels. Most shells had a fresh appearance, given their transparent colour.

Distribution: Known from a spring in Vilaverd (Font del Mas) and two springs at Montblanc (Font de la Ceba and Font del Llorach), all at the Francolí River basin.

Differentiating characters: The main differences between the new subspecies T. raveni incisum and the subspecies is the presence of an incision in the lower part of the peristome ( Fig. 2 View FIGURE 2 ).

Although we consider the new taxon as a subspecies, given its geographic separation with the two known populations of the subspecies (from the Gaià River basin), and the presence of constant and distinctive shell characters between them, it cannot be ruled out that it may represent a fully differentiated species. Since the shells of both taxa are quite similar in overall characters, and in the absence of anatomical or genetic data, or any likely intermediate population, we cautiously consider it a subspecies. In any case, this work shows the richness of our groundwater ecosystems, which have been only superficially examined until now.