Tegella armifera (Hincks, 1880)
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publication ID |
https://doi.org/ 10.1007/s13127-022-00562-y |
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persistent identifier |
https://treatment.plazi.org/id/03AC87AF-FFA2-FFB9-FC98-CC52861F9E66 |
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treatment provided by |
Felipe |
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scientific name |
Tegella armifera |
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Tegella armifera View in CoL ( Figs. 1E View Fig , 11 View Fig , 18B)
Avicularium
Cystid and mandible This species has elongated adventitious avicularia of two size categories. Larger avicularia are associated with the distal part of the ooecium (protective capsule of the ovicell, Fig. 11A View Fig ), smaller ones with the proximal gymnocyst of non-ovicellate autozooids. Both categories are similar in shape and structure.
In both cases, the avicularian cystid is elongate-triangular in a frontal plane, with pointed rostrum directed distally or disto-laterally and semicircular postmandibular area with a narrow cryptocyst.
The triangular mandible covers the palate, and its pointed shape corresponds to the shape of the rostrum. Proximally, the mandible is connected to the frontal membrane occupying the smaller postmandibular area. The mandible is comprised of three walls (upper, lower, and vertical/transverse) with enclosed cavity, and of the thickened, rather wide peripheral sclerite whose tip is pointed and curved down ( Figs. 11B–D View Fig , 18B). The lower mandibular wall is partially internal, with the upper vestibular wall attached to the sclerite ( Fig. 11B View Fig ). In some histological preparations, this wall looked folded, and this aspect requires further study. The mandible cavity communicates with the avicularian body cavity through a small oval opening in the transverse wall connecting the upper and lower walls of the mandible.
Polypide and muscular system The vestigial polypide is situated under the palate ( Figs. 11D View Fig , 18B). In its uppermost part, the tentacle sheath bears two diaphragmatic muscles tudinal muscles of tentacle sheath visible in C). D Transverse section of avicularium. In E dotted line indicates borders of avicularian mandible. Abbreviations: dm, diaphragm, fm, frontal membrane, g, ganglion of vestigial polypide, mab, abductor, mad, adductor, md, mandible, p, palate, rm, retractor muscles, sc, sclerite of mandible, t, tendon of adductor, uv, upper wall of vestibulum, vp, vestigial polypide striation in its retractors). F–H Muscular elements of avicularium (latero-frontal views) (note longitudinal muscles of tentacle sheath visible in F, and distal non-paired abductor in F and H). Small opening in transverse mandibular wall is visible in D and H (arrowhead). Abbreviations: dm, diaphragm, fm, frontal membrane, mab1, distal non-paired abductor, mab2, proximal paired abductors, mad, adductor, md, mandible, p, palate, pa, papilla of vestigial polypide, pe, peduncle, rm, retractor muscles, ro, rostrum, t, tendon of adductor, ts, tentacle sheath, uv, upper wall of vestibulum, vp, vestigial polypide (upper thick, forming smaller ring, and lower thin, forming wider ring, the latter not seen in Fig. 11 View Fig ), and several (5–7) longitudinal muscle fibers whose distal ends reach the lower ring muscle of the diaphragm. At least three thin polypide retractor muscles distally attach to the tentacle sheath ( Fig. 11C, D View Fig ).
The two smooth abductors are comprised of 5–7 relatively short muscle bundles each ( Fig. 11C, E View Fig ). These bundles have approximately the same width and length, consisting of several muscle fibers each. Distally, they attach to the frontal membrane within two parallel zones, whereas their proximal ends anchor to the lateral cystid walls in the proximal part of the avicularium. When viewed from above, the abductors overlap slightly with the proximal portions of large “conical” adductors.
Striated adductors occupy most of the cystid volume. They arise from the basal and lateral cystid walls and insert in the upper vestibular wall by two tendons that reach the proximal margin of the mandible sclerite ( Figs. 11B View Fig , 18B).
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