Philactinoposthia brevis, Nilsson, Karin Sara, Wallberg, Andreas & Jondelius, Ulf, 2011

Nilsson, Karin Sara, Wallberg, Andreas & Jondelius, Ulf, 2011, New species of Acoela from the Mediterranean, the Red Sea, and the South Pacific, Zootaxa 2867, pp. 1-31 : 3

publication ID

https://doi.org/ 10.5281/zenodo.277458

DOI

https://doi.org/10.5281/zenodo.5683931

persistent identifier

https://treatment.plazi.org/id/03A6456D-FFB7-AE40-FF4B-9189FBC7FF49

treatment provided by

Plazi

scientific name

Philactinoposthia brevis
status

sp. nov.

Philactinoposthia brevis sp.nov.

( Figs. 1 View FIGURE 1 , 2 View FIGURE 2 , 3 View FIGURE 3 )

Type Material: Holotype: SMNH Type-8041. Paratype 1: SMNH Type-8042, Paratype 2: SMNH Type-8043.

Type Locality. Red Sea, Eilat (29° 30' 2" N, 34° 55' 36" E), at 15 m water depth in fine sand.

Other Material examined. Living specimens in squeeze preparations; 4 sets of 4-5 μm serial sagittal sections of paraffin-embedded specimens.

Etymology. Brevis = short, small in latin, and refers to the short body size, small bursal nozzle and small copulatory organ.

Description. Active swimmer. Living specimens up to 500 μm long and ~85 μm wide. Body shape cylindric, both ends rounded. Epidermis completely ciliated with cilia that are 4 μm long. Brown colored rhabdoid glands present, 10 μm long, sparsely scattered across body, absent in anterior end and almost completely lacking on ventral side ( Fig. 1 View FIGURE 1 AE). Rhabdoid glands compact with oval shape in sections, separate rods not detectable. Epidermis uncolored in transmitted light. Statocyst, 8 μm in diameter, located 50 μm from anterior end, U10.

Frontal organ present, cell bodies of frontal organ extend from U0 to U20. Mouth ventral, located in middle of body. Digestive central syncytium with brownish coloration, extends from U20 to U80.

Ovary unpaired, one large oocyte, extends from level of mouth to bursal nozzle, U65 to U82 ( Fig. 1 View FIGURE 1 BDE). Female gonopore ventral, positioned posteriorly at U84, opens to small globular seminal bursa with bursal nozzle that connects anteriorly, difficult to detect in live specimens ( Fig. 1 View FIGURE 1 BD). Bursal nozzle ~30 μm long with a zigzaglike appearance.

Male gonopore ventral, positioned posteriorly at U90, opens immediately to small arrow-shaped male copulatory organ with sclerotized stylet needles surrounded by sperm. At least four needles detectable, short in relationship to body size, 30 μm long ( Fig. 1 View FIGURE 1 B). Glands surrounds copulatory organ ( Fig. 1 View FIGURE 1 D). False seminal vesicle located at proximal end of stylet-like structure. Sperm with granules ( Fig. 1 View FIGURE 1 BC).

SMNH

Saskatchewan Museum of Natural History

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