Habeastrum tayos Hausdorf, Roosen & 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 tayos

<p><i>Habeastrum tayos</i> Hausdorf, Roosen & Tapia sp. nov.</p><p>Fig. 1 G – L, Tables 1, 2</p><p><b>Type material.</b></p><p><i>Holotype</i>: Ecuador, Pastaza province: • Puyo, Chiwitayu, Cueva de los Tayos area, 1.9478°S, 77.7875°W, 740 m a. s. l., 07. 11. 2025, E. Tapia & A. Guasti leg., QCAZI 282656. <i>Paratypes</i>: Ecuador, Pastaza province: • same data as holotype. QCAZI 282657 / 1; ZMH -MOL-165103 / 5. • Puyo, Chiwitayu, Cueva de los Tayos area, 1.9477°S, 77.7877°W, 750 m a. s. l., 07. 11. 2025, E. Tapia & A. Guasti leg., ZMH -MOL-165577 / 1. • Puyo, Chiwitayu, Cueva de los Tayos area, 1.9475°S, 77.7879°W, 760 m a. s. l., 08. 11. 2025, E. Tapia & A. Guasti leg., ZMH -MOL-165578 / 2. • Puyo, Chiwitayu, Cueva de los Tayos area, 1.9473°S, 77.7875°W, 750 m a. s. l., 08. 11. 2025, E. Tapia & A. Guasti leg., INABIO -MCL-1255 / 1, ZMH -MOL-165579 / 1. • Puyo, Chiwitayu, Cueva de los Tayos area, 1.9479°S, 77.7873°W, 720 m a. s. l., 08. 11. 2025, E. Tapia & A. Guasti leg., QCAZI 282658 / 3, ZMH -MOL-165580 / 3. • Puyo, Chiwitayu, Cueva de los Tayos area, 1.9481°S, 77.7869°W, 730 m a. s. l., 09. 11. 2025, E. Tapia leg., QCAZI 282659 / 2, ZMH -MOL-165581 / 2. • Puyo, Chiwitayu, Cueva de los Tayos area, 1.9482°S, 77.7867°W, 730 m a. s. l., 09. 11. 2025, E. Tapia leg., QCAZI 282660 / 1, ZMH -MOL-165582 / 2. – Ecuador, Morona-Santiago province: • Sunka Biological Station, sampling station SU 7, 2.0667°S, 77.7500°W, 1032 m a. s. l., 01. 03. 2026, M. T. Roosen & L. Tucupi Catan leg., INABIO -MCL-1253 / 1, INABIO -MCL-1254 / 1.</p><p><b>Other material.</b></p><p>Ecuador, Napo province: • Tena, Cotundo, Santa Helena de los Guacamayos towards Cosanga, 0.6609°S, 77.7930°W, 1700 m a. s. l., 07. 11. 2025, D. Kammin, K. Kopp & E. Tapia leg., ZMH -MOL-165576 / 1. Chaco, Oyacachi, 0.22109°S, 78.04959°W, 3090 m a. s. l., 16. 11. 2025, D. Kammin, K. Kopp & E. Tapia leg., ZMH -MOL-165583 / 1.</p><p><b>Diagnosis.</b></p><p>Shell minute (1.2–1.6 mm high), white, elongated conical, with 4.5–6 strongly convex whorls, coarse ribs (8–12 ribs / 0.5 mm), and a narrow umbilicus taking 7 % of the shell diameter.</p><p><b>Description.</b></p><p>Shell elongated conical; 4.5–6 strongly convex whorls; protoconch (c. 2 whorls) with a dense pattern of wavy wrinkles; teleoconch coarsely ribbed (8–12 ribs / 0.5 mm on ventral side of body whorl); white; aperture circular, prosocline; peristome continuous, attached to body whorl, not expanded, not reflexed and hardly thickened on the inside; umbilicus open, narrow, taking up to 7 % of shell diameter. Measurements see Table 2.</p><p><b>Etymology.</b></p><p>The specific epithet refers to the oilbird (<i>Steatornis caripensis</i> Humboldt, 1817), also known as the ‘ tayo’ in Spanish (used as a noun in apposition). This species breeds in caves, many of which are named after it, including caves at the type locality and around Sunka.</p><p><b>Distribution.</b></p><p><i>Habeastrum tayos</i> sp. nov. is known from piedmont evergreen forest on limestone outcrops in the Amazonian Cordilleras in Pastaza and Morona-Santiago provinces at 720–1032 m a. s. l. It was found in litter between calcareous rocks. Similar shells were found at higher altitudes in low montane evergreen forest of the northern Eastern Andes (1700 m a. s. l.) and in high montane evergreen forest of the northern Eastern Andes (3090 m a. s. l.) in Napo province. There they occurred in a very acidic habitat without calcareous rocks. Their specific identity has to be proven, given the different habitats. There were no statistical differences between the eleven measured specimens from Pastaza and the two specimens from the Eastern Andes in the shell dimensions (Student’s t-tests, two-tailed: diameter of shell, <i>p</i> = 0.37; height of shell, <i>p</i> = 0.27).</p><p><b>Remarks.</b></p><p><i>Habeastrum tayos</i> sp. nov. differs from all the other known <i>Habeastrum</i> species in the much coarser ribbing (Table 2).</p>