Odostomia (s.l.) sp. 1

Albano, Paolo G., Steger, Jan, Bakker, Piet A. J., Bogi, Cesare, Bosnjak, Marija, Guy-Haim, Tamar, Huseyinoglu, Mehmet Fatih, LaFollette, Patrick I., Lubinevsky, Hadas, Mulas, Martina, Stockinger, Martina, Azzarone, Michele & Sabelli, Bruno, 2021, Numerous new records of tropical non-indigenous species in the Eastern Mediterranean highlight the challenges of their recognition and identification, ZooKeys 1010, pp. 1-95 : 1

Odostomia (s.l.) sp. 1 Figure 23

New records.

Israel • 1 spcm; Haifa Bay; 32.8211°N, 35.0196°E; depth 11 m; 2 Aug. 2015; soft substrate; grab; NM project (sample HM27(c)); size: H 1.4 mm, W 0.7 mm (illustrated specimen) • 8 spcms; 31.9364°N, 34.6846°E; depth 20.2 m; 11 Oct. 2012; sandy substrate; grab; Via Maris project (sample VM40).

Remarks.

This species is characterized by a translucid-white, cylindrical shell with ~ 3 whorls, and an intorted protoconch of type C (Figure 23I ) whose columella is oriented at an angle of ~ 160° relative to the teleoconch axis (revealed by µCT-imaging, Figure 23H and additional scans available at https://doi.org/10.6084/m9.figshare.c.5215226). The growth lines are slightly prosocline on the spire while becoming almost orthocline on the body whorl; an extremely faint spiral microsculpture is present on the apical part of the whorls, but only visible in high-magnification SEM images (Figure 23G ). This species differs from Odostomia cf. dalli by its smaller size (height up to 1.4 mm), the more cylindrical shape, shallower suture, and the absence of a visible columellar tooth. Although this species, in terms of size and overall shape, somewhat resembles representatives of the fresh- and brackish water-dwelling family Hydrobiidae , the fact that numerous living specimens were found in a fully marine environment and its heterostrophic protoconch unambiguously identify it as member of the family Pyramidellidae .

Odostomia sp. 1 does not resemble any known Mediterranean pyramidellid; considering the great number of confirmed introductions of Indo-Pacific microgastropods to the eastern Mediterranean Sea, we therefore suspect that also this taxon might be a Lessepsian species. Among Indo-Pacific Odostomiinae , O. bullula Gould, 1861 (e.g., Johnson 1964; Robba et al. 2004) is similar to our specimens, but differs by its more conical shape and larger size (height to 2 mm, width to 1 mm). Another similar species, O. decouxi Saurin, 1959, was suggested to be a junior synonym of O. bullula ( Robba et al. 2004).

Figures

Figure 23. Odostomia (s. l.) sp. 1, Haifa Bay, Israel, NM project (sample HM 27 (c )): front (A, B), side (C, D) and back (E, F) views, detail of the adapical part of the body whorl showing the extremely faint spiral microsculpture (G), virtual section through the apical spire showing the columella of the intorted protoconch (H) and apical view of the protoconch (I; surface partly corroded). The pink hue is due to staining with eosin solution. Scale bars: 0.5 mm (A-F); 0.2 mm (G-I).