Schellencandona antoniae, Rossetti & Mazzini & Bruno, 2025

Schellencandona antoniae sp. nov.

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( Figures 1–3 View FIGURE 1 View FIGURE 2 View FIGURE 3 )

Type locality. Toncina Stream , approximately 600 meters upstream of its confluence with the Ceno River , near the locality of Molino dei Belli , in the municipality of Bardi , Parma, Italy. Latitude 44°35’39.9”N, longitude 9°42’15.8”E, elevation about 430 m a.s.l. GoogleMaps

Type material. Holotype: adult ♀ ( MZUF726 View Materials , LV: L=575 µm, H=360 µm; RV: L=564 µm, H=311 µm) collected on July 13, 2018: soft parts dissected in glycerine in a sealed slide, valves stored dry in a micropalaeontological slide . Paratypes: adult ♀ ( MZUF727 View Materials , Cp: L=550 µm, H=340 µm) collected on August 3, 2018: soft parts dissected as the holotype, valves lost during dissection; adult ♀ ( MZUF728 View Materials , LV: L=543 µm, H=332 µm; RV: L=539, H=298 µm) collected on July 13, 2018: soft parts dissected as the holotype and valves stored dry in a micropalaeontological slide; adult ♀ ( MZUF729 View Materials , RV: L=533 µm, H=299 µm) collected on November 16, 2024: isolated RV stored dry in a micropalaeontological slide. The specimens were collected by Linda Faè in 2018 and by GR in 2024 .

Etymology. This new species is dedicated to, and named, in honour of Antonia Cavalieri, a passionate naturalist devoted to the preservation of the environment and biodiversity, who also happens to be the beloved wife of the first author.

Description of female. Valves trapezoidal in lateral view ( Fig 1A–B, G View FIGURE 1 ). LV larger than RV. Greatest H slightly less than ½ L and located slightly behind mid-length. Greatest L below mid-height.Anterior margin broadly rounded, posterior margin narrowly rounded. Dorsal margin straight, tapering posteriorly, gently arched on LV, posteriorly slightly sloping, more steeply than anteriorly. On RV, anterior cardinal angle slightly concave. Reticulate surface organized in strongly calcified polygonal muri and smooth fossae. Normal pore canals simple. Hinge adont ( Fig 1C– D, E View FIGURE 1 ): LV with smooth groove; RV with smooth bar. In internal view ( Fig 1C–D, E View FIGURE 1 ), calcified part of inner lamella wide anteriorly. Ventral margin of LV with slight but distinct convexity in the middle, complementary expansion of selvage on RV. Central muscle scar arrangement as characteristic for Candoninae ( Fig 1F View FIGURE 1 ).

A1 seven-segmented ( Figure 2A View FIGURE 2 ); first segment bearing a seta along ventral margin and two long, apical-dorsal setae of similar length; second and third segments with one ventral seta each, both slightly exceeding and reaching the margin of next respective segment; fourth and fifth segments with one long apical-ventral seta and one tiny apical-dorsal seta each; sixth segment with three long apical setae, one tiny apical-dorsal seta and seta α slightly exceeding the margin of next segment; seventh segment with a long aesthetasc ya and three apical setae, two of which very long and the most dorsal one as long as about the last two segments together.

A2 ( Figure 2B View FIGURE 2 ): protopodite two-segmented, first segment (not shown) with two ventro-apical setae and one long dorsal seta, second segment with long subapical seta on ventral edge. Exo with long seta reaching 4/5 of next segment and two tiny setae, the ventral-most one with enlarged base. Endopodite three-segmented; first segment with aesthetasc Y inserted just below half of ventral margin and reaching approximately to distal edge of same segment, and two ventro-apical setae, the longest one extending slightly beyond distal margin of last endopodal segment, and about 2.5 times as long as the other; second endopodal segment with seta at mid-dorsal margin just surpassing distal end of segment, aesthetasc y1 proximally on ventral margin, three unequal t setae inserted about mid- segment, three short z setae, dorso-apical claws G1 and G2 with length ratio c. 4:1, apical-ventral claw G3 reaching to tips of claws G1 and GM, aesthetasc y2 barely exceeding distal margin of next segment; last endopodal segment distally with claw Gm and GM in a ratio of 1 to 2, and more ventrally aesthetasc y3 with thin accompanying seta; GM about twice as long as combined length of last two endopodal segments; g seta not observed.

Md (not shown): palp four-segmented; first segment with long seta, S1 seta slightly longer than former one, short alpha seta and S2 seta short and stout on distal part of ventral margin; second segment with ventrally three long, subequal setae (setal group), a short beta seta and an additional seta extending to just before distal end of last segment, and two dorsal setae of different lengths in subapical position; apical part of third segment with three dorsal setae, a ventral seta and centrally a gamma seta long and smooth; last segment with two ventral setae and two dorsal claws, the innermost one stout and with enlarged base. Coxa narrow.

Mx ( Figure 2C View FIGURE 2 ): palp two-segmented; first segment bearing four setae of which three in outer position and one more central; second segment with two robust, long setae and four shorter, thinner setae.

T1: damaged in the available specimens.

T2 ( Figure 3A View FIGURE 3 ): five-segmented; basis (not shown) perhaps lacking d1 seta; second segment with antero-distal seta e; third and fourth segments weakly subdivided, with f and g seta respectively; last segment with h1 seta slightly shorter than bearing segment, stout apical h2 claw about six times longer than terminal segment and tiny h3 seta in subapical, posterior position.

T3 ( Figure 3B View FIGURE 3 ): protopodite with short d1 seta and long dp seta, the latter exceeding distal end of next segment; endopodite with three segments; first endopodal segment without setae, second segment with subapical g seta; third segment with three setae: h1 short, h2 strong and h3 long and thin, with length ratio approximately 1:2.7:3.1.

CR ( Figure 3C View FIGURE 3 ): rami stout, with long seta sp and strongly reduced seta sa; terminal claws robust and serrated, Ga length approx. 1.2 times Gp and 0.9 times the ramus length.

CR attachment ( Figure 3D View FIGURE 3 ): straight, branched at both ends.

Eye pigment absent.

Description of male. Male unknown.

Accompanying ostracods. One specimen of Cypria ophtalmica ( Jurine, 1820) and an unidentified ostracod larval stage collected on 4 July 2018.

Remarks

Schellencandona antoniae sp. nov. is formally described here, despite only a few female specimens being available. We have chosen to proceed with the description as both valve and soft-part characteristics are provided, enabling us to clearly distinguish the new species from its congeners, even in the absence of important diagnostic features of the male which, although not found, is presumed to exist (see Discussion). Furthermore, repeated samplings at the type locality to collect additional specimens to be studied were unsuccessful.