Baltalimania asinariensis, Atherton & Jondelius, 2022

Atherton, Sarah & Jondelius, Ulf, 2022, Diversity in the family Isodiametridae (Acoela): New species bring back old problems, Zootaxa 5169 (5), pp. 401-424 : 404-408

Baltalimania asinariensis sp. nov.

Figures 3

Zoobank registration. urn:lsid:zoobank.org:act:A12B4C50-5E92-4CDF-B49D-748479A4DE01

Materials examined. Digital video and photographs of original living specimen, Holotype ( SMNH Type-9424)

Type locality. Cala Stagno Lungo , Asinara Island, Italy, 41°03’53 N, 8°17’03 E

Habitat. 0.3–1 m depth, marine, medium sand.

Diagnosis. Body length 0.4–0.6 mm. Body clear and without pigmentation. Frontal organ small. Rhabdoid glands in longitudinal rows. Posterior vacuole present. Paired testes and ovaries. Seminal bursa present just posterior to largest egg. Male copulatory organ large, with penis partially invaginated into the seminal vesicle. Penis 17–20 µm long, curved. Antrum masculinum small, ciliated. Male gonopore subterminal.

Etymology. This species is named for its type locality, Asinara Island.

Description. Living specimen 0.45–0.60 mm long and to 0.12 mm width at midpoint. Free-swimming specimens lively and quick. Elongate with rounded anterior and posterior ends. Body colorless, without pigmentation and clear. Numerous lipid droplets of varying sizes present in digestive parenchyma and throughout the body, clear to yellow in color. Digestive parenchyma extends from just posterior of statocyst to level of posterior egg. Mouth not observed.

Frontal organ small, just reaching level of statocyst. Statocyst present 70 µm from anterior end, 10–12 µm in diameter with 6–7 µm statolith. Posterior vacuole present.

Epidermis completely ciliated. Cilia 4–6 µm long. Rhabdoid glands clearly distributed in longitudinal rows. Rhabdoid glands partially subepidermal, colorless, 6 µm in length.

Ovaries and testes paired. Small seminal bursa present, located just below largest egg and typically with sperm. Bursa indistinct without walls or ornamentation, globular, 26–30 µm long and 16–18 µm wide. Separate female gonopore present at ventral midline ~70 µm from posterior end of animal.

Male copulatory organ large, 39–40 µm long and 36–36 µm wide. Globular. Penis invaginated into the seminal vesicle and extending into the antrum masculinum. Isodiametric penis curved, 17–20 µm long. Antrum masculinum short, ciliated. Male gonopore at ventral midline.

Figures

FIGURE 3. Baltalimania asinariensis sp. nov. A. micropictograph of the whole body. B. drawing of the whole body C. micropictograph of the posterior focusing on the reproductive structures; b bursa, dp digestive parenchyma, eg egg, f frontal organ, fp, female gonopore, l lipid globule, mco male copulatory organ, mp male gonopore, p penis, r rhabdoid glands, st statocyst, t testes, v vacuole