Schwartziella triticea ( Pease, 1861 )

Qi, Lu, Liu, Songyuan, Sun, Shengming, Kong, Lingfeng & Ma, Zhenhua, 2025, Zebinidae (Caenogastropoda, Rissooidea) from Hainan Island, China, with re-description of four species, Biodiversity Data Journal 13, pp. e 165463-e 165463 : e165463-

Schwartziella triticea ( Pease, 1861)

Materials

Type status: Other material. Occurrence: catalogNumber: XCL 59 ; recordedBy: Qi Lu; individualCount: 1; lifeStage: adult; occurrenceID: 20A6B31E-18D4-513E-9DB0-3DA25563A15D; Taxon: taxonID: Native; scientificName: Schwartziella triticea ; originalNameUsage: Rissoina triticea Pease, 1861 , Rissoina rissoi Weinkauff, 1881 ; Location: country: China; stateProvince: Hainan; locality: Chiling ; Identification: identifiedBy: Qi Lu; dateIdentified: 2023

Description

Shell minute (3.4 ± 0.25 mm in height; 1.5 ± 0.01 mm in width), fusiform-ovate in shape, white, solid and translucent (Fig. 1 A and B). Seven whorls, body whorl height greater than spire (Fig. 1 C and D); teleoconch whorls 4, inflated, sculptured exclusively by axial ribs with wide intercostal spaces (approximately twice the width of ribs), axial ribs on body whorl constricted at base (Fig. 1 C-F); shell surface with fine microsculpture (Fig. 1 F). Suture distinct, but shallow (Fig. 1 F). Aperture large, D-shaped, angulated posteriorly, without anterior channel; outer lip prosocline, thick, with varix, bearing fine growth lines on edge; inner lip and columellar lip forming straight line, thick, broad, everted at columella; interior of aperture with delicate annular sculpture (Fig. 1 E). Base lacking folds. Umbilicus absent. Protoconch of 3 whorls, eroded (Fig. 1 G and H).

Diagnosis

Shell somewhat fusiformly ovate; ribs nine, prominent, smooth, continuous over the sutures; aperture ovate ( Pease 1861).

Distribution

Schwartziella triticea exhibits a broad tropical distribution, ranging from the Red Sea across the Indian Ocean. It is also recorded from Hainan Island ( China) and Hawaiian waters ( Sleurs and Strack 2021).

Taxon discussion

The genus Schwartziella Nevill, 1881 is primarily characterised by prominent axial ribs on the shell surface, with ribs on the body whorl extending continuously to the base. It differs from Rissoina in lacking an anterior canal in the aperture and possessing an inner operculum without peg-like projections. When compared to Zebina H. Adams & A. Adams, 1854 , Schwartziella Nevill, 1881 shows minimal anatomical distinctions, but exhibits more robust axial ribbing. S. triticea closely resembles S. laseroni (C. - K. Chang & W. - L. Wu, 2004) ; however, the latter can be distinguished by the presence of basal plicae and a narrower columellar lip.

Figures

Figure 1. Schwartziella triticea (Pease, 1861). A, B shell illustration in colour; C scanning electron micrographs of frontal view of shell; D scanning electron micrographs of lateral view of shell; E detail of aperture; F detail of teleoconch surface; G scanning electron micrographs of lateral view of protoconch; H scanning electron micrographs of apical view of protoconch.