Habeastrum striolatum Hausdorf & Tapia 2026, sp. nov.
Authors: Hausdorf, Bernhard, Roosen, Marijn T., Tapia, Elicio
Type: Taxonomic treatment
Published: 2026-08-03
Keywords: Biodiversity, Taxonomy, Animalia, Mollusca, Gastropoda, Architaenioglossa, Diplommatinidae, Habeastrum, Habeastrum striolatum

<p><i>Habeastrum striolatum</i> Hausdorf & Tapia sp. nov.</p><p>Fig. 1 A – F, Tables 1, 2</p><p><b>Type material.</b></p><p><i>Holotype</i>: Ecuador, Pastaza province: • Puyo, Chuwitayo, Cueva de los Tayos, inside the cave on the bottom of a 100 m vertical sinkhole, 1.9511°S, 77.7884°W, 740 m a. s. l., 24. 11. 2025, E. Tapia leg., QCAZI 282654. <i>Paratypes</i>: • same data as holotype: QCAZI 282655 / 1; ZMH -MOL-165097 / 2.</p><p>D, large diameter of shell; H, height of shell; n, number of measured individuals; std. dev., standard deviation; U, width of umbilicus; W, number of whorls.</p><p>D, large diameter of shell; H, height of shell; da, diameter of aperture; ha, height of aperture; R, ribs / 0.5 mm on body whorl; U, width of umbilicus; W, number of whorls.</p><p><b>Diagnosis.</b></p><p>Shell minute (1.3 mm high), white, elongated conical, with 5.25–5.5 strongly convex whorls, protoconch with indistinct, radial wrinkles, teleoconch with dense riblets (26–38 ribs / 0.5 mm), and a narrow umbilicus taking 9–11 % of the shell diameter.</p><p><b>Description.</b></p><p>Shell elongated conical; 5.25–5.5 strongly convex whorls; protoconch (c. 2 whorls) with indistinct, radial wrinkles; teleoconch with dense riblets (26–38 riblets / 0.5 mm on ventral side of body whorl); white; aperture almost circular, prosocline; peristome continuous, attached to body whorl, not expanded, not reflexed and hardly thickened on the inside; umbilicus open, narrow, taking 9–11 % of shell diameter. Measurements see Table 2.</p><p><b>Etymology.</b></p><p>Named after the striolate sculpture with fine linear ridges (Latin striolatus, striated, used as an adjective).</p><p><b>Distribution.</b></p><p><i>Habeastrum striolatum</i> sp. nov. is known only from the inside of the Cueva de los Tayos in piedmont evergreen forest on limestone outcrops of the Amazonian Cordilleras in Pastaza province in Ecuador at 740 m a. s. l.</p><p><b>Remarks.</b></p><p><i>Habeastrum striolatum</i> sp. nov. resembles the sympatric <i>Habeastrum tayos</i> sp. nov. in shell form and size, but differs from it in the finer and denser ribbing (Table 2). <i>Habeastrum striolatum</i> sp. nov. is smaller than the Brazilian <i>Habeastrum</i> species. Concerning shell form, <i>Habeastrum striolatum</i> sp. nov. is intermediate between the shorter conical <i>Habeastrum omphalium</i> Simone, 2019, and longer conical <i>Habeastrum strangei</i> Simone, Cavallari & Salvador, 2020. <i>Habeastrum parafusum</i> Simone, 2019 has a more cylindrical-conical shell. The sculpture of <i>Habeastrum striolatum</i> sp. nov. (26–38 riblets / 0.5 mm on ventral side of body whorl) is most similar to that of <i>H. omphalium</i> (ca. 22 riblets / 0.5 mm), but this species has faint spiral lines between the ribs, which are lacking in <i>H. striolatum</i> sp. nov. The ribbing is more dense in <i>H. parafusum</i> (ca. 40 riblets / 0.5 mm), and less dense in <i>H. strangei</i> (ca. 9 riblets / 0.5 mm).</p>