Charisactis tetiana, Ocaña & Çinar, 2018

Ocaña, Oscar & Çinar, Melih Ertan, 2018, Descriptions of two new genera, six new species and three new records of Anthozoa (Cnidaria) from the Sea of Marmara, Journal of Natural History 52 (35 - 36), pp. 2243-2282 : 2260-2263

Charisactis tetiana gen. nov. et sp. nov.

( Figures 11 and 12 )

Material examined

Holotype; ESFM-CNI/2013-20 , 26 June 2013, Sea of Marmara , Y49, 41°09 ʹ 26 ʺ N, 29°03 ʹ 10 ʺ E, 50 m, sandy mud with shell fragments, moderately retracted, longitudinal sectioned to

study the anatomy and cnidom, 0.8 cm × 0.3 cm; Paratype, ESFM-CNI/2013-21 ; 26 June 2013, Sea of Marmara , Y49, 41°09 ʹ 26 ʺ N, 29°03 ʹ 10 ʺ E, 50 m, sandy mud with shell fragments, 1 medium size specimen strongly retracted, rest of cuticle along the column, cross sectioned to study the anatomy and cnidom, 0.2 – 1 cm × 0.2 – 0.5 cm, 5 specimens .

Description

Body retracted, triangular in shape; colour pale yellowish ( Figure 11 (a)). Pedal disc wide and more or less rounded ( Figure 11 (a)). A deciduous cuticle covering body wall. Tentacles clearly entacmeic and some of them with strong ectodermal musculatures. No sphincter ( Figure 11 (b)). Thin mesogloea with some ectodermal muscular developments. Three mesentery cycles: 6 + 6 + 12; six complete, six microcnemes with parietobasilar developments and absence of retractors; third cycle present including 12 very short microcnemes without musculatures. Pharynx folded with two large syphonoglyphs and their directives ( Figure 11 (c)). First cycle mesenteries with very strong reniform restricted retractors ( Figure 11 (d)).

Cnidome

A survey of the cnidom is summarized in Table 4 and Figure 12 . Due to the retracted specimens and poor body condition, examination on the internal tissues was difficult. General survey of the cnidom was done, but we do not reject some slight modifications occurring specially in the filaments. Splitting penicilli B into two categories or changing the abundance of thick spirulae seems to be possible ( Figure 12 ). In addition, two penicilli categories can be found in the pharynx. However, such new arrangement requires more material to be examined.

Remarks

The family Condylanthidae includes a heterogeneous group of species with different morphological characters, and with the exception of the genus Segonzactis all of them are monotypic. According to Sanamyan (2001), most genera of Condylanthidae have rarely been reported again after the original descriptions. Rieman-Zürneck (1979) emended characters to the diagnosis of Condylanthidae family and described a new genus, Segonzactis , from deep waters. This genus includes two species, Segonzactis platypus Riemann-Zürneck, 1979 and Segonzactis hartogi Vafidis and Chintiroglou 2002 (Riemann-Zürneck 1979; Vafidis & Chintiroglou 2002). The main differences between Segonzactis and Charisactis gen. nov. are that the former genus has different basilar musculature, an atypical mesenteries arrangement, single siphonoglyph and a very simple cnidom with a few capsule categories. The other genus within Condylanthidae that is morphologically similar to Charisactis gen. nov. is Charisea , as it also does not have psedudospherules, sphincter and circumscribed retractors. However, the genus Charisea has a reduced pedal disc and an elongate body wall (see Carlgren 1934; Sanamyan 2001), whereas Charisactis gen. nov. has a broad pedal disc. Cnidom is also an important character to take into account: more categories are present in the tentacles and filaments of Charisactis gen. nov. when compared to those in Charisea . Furthermore, the presence of homotrichs in the tentacles and body wall of Charisactis gen. nov. is another important difference between these two genera.

Habitat

This species was found at 50 m depth on shell fragments.

Etymology

The species name is dedicated to the ancient Tethys Sea.

Figures

Figure 11. Charisactis tetiana sp. nov. (a) Oral view of a specimen; (b) longitudinal section of the body showing the absence of sphincter; (c) directive retractors and syphonoglyph; (d) retractors at the pharynx level staining in toto. Scale bars: a = 2 mm; b = 1 mm; c = 0.9 mm; d = 1.6 mm.

Figure 12. Charisactis tetiana sp. nov. Cnidom morphology in different parts of the body. (a) Spirocyst; (b) penicilli B; (c) spirulae; (d) homotrich; (e) spirulae; (f) penicilli A; (g) penicilli B; (h) spirulae; (j) spirulae; (k) penicilli A; (l) penicilli B; (m) spirulae; (n) homotrich; (o) penicilli A; (p) spirulae. Scale bar 15 µm.