Crypthelia formosa Cairns, 1983a, Cairns, 1983

Bernal, M. C., Cairns, S. D., Penchaszadeh, P. E. & Lauretta, D., 2021, Stylasterids (Hydrozoa: Stylasteridae) from Mar del Plata submarine canyon and adjacent area (southwestern Atlantic), with a key to the species off Argentina, Zootaxa 4969 (3), pp. 401-452: 12-14

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Crypthelia formosa Cairns, 1983a


Crypthelia formosa Cairns, 1983a  

( Fig. 4b View FIGURE 4 ; Fig. 6 View FIGURE 6 )

Crypthelia formosa Cairns 1983a: 133–136   , figs. 31g, 39a–f, 40a–c, map 12; Cairns 1983b: 431, table 1; Cairns 2015: 310; Río Iglesias et al. 2012: 191; Bax & Cairns 2014: 107, table 1, 109, 110, map 3

Distribution. Patagonia, 42° S to 48° S; Scotia Arc from Tierra del Fuego to South Georgia, 483–1841 m; Burdwood Bank, 1647–2044 m. New record off Mar del Plata, 877–1398 m.

Material examined. USNM 60207 View Materials (holotype) off Burdwood Bank , Eltanin St. 1592 (54° 43–45’ S, 55° 30–37’ W)   ; USNM 60087 View Materials (paratype) off Scotia Arc , Vema St.   17–61 (54° 44’ S, 55° 39’ W) GoogleMaps   ; MACN-In 40647 off Mar del Plata , Argentina, St. 59 (37° 49.688’ S, 54° 5.236’ W), 1398 m, September 2013; GoogleMaps   MACN-In 40648 off Mar del Plata , Argentina, St. 42 (37° 59.110’ S, 54° 41.136’ W), 877 m, May 2013; GoogleMaps   MACN-In 40649 off Mar del Plata, Argentina, St. 59 (37° 49.688’ S, 54° 5.236’ W), 1398 m, September 2013; GoogleMaps   MACN-In 42501 off Mar del Plata, Argentina, St. 37 (37° 59.848’ S, 54° 24.206’ W), 1275 m, May 2013 GoogleMaps   .

Description. Fragments delicate with uniplanar growth. Presence of polychaete tube on posterior face induces anastomosis and thickening of branches bearing it ( Fig. 4b View FIGURE 4 ) or deviation of plane of growth. Largest fragment 3.8 cm wide and 3.8 cm tall with basal branch 4.0 mm thick. Branches round in cross section. Distal branches, 0.6–1.0 mm thick, bear cyclosystems considerably wider, resembling beads on a string ( Fig. 6a View FIGURE 6 ). Branching dichotomous, two branches originating laterally from one cyclosystem. Coenosteum white and porcellaneous, with a linear-imbricate texture especially conspicuous along slender branches ( Fig. 6c View FIGURE 6 ), that turns reticulate-imbricate to reticulate-granular in cyclosystems and polychaete tube. Coenosteal strips convex, 58–104 µm wide and bordered by longitudinal rows of short slits pierced by one or two deep pores.

Cyclosystems round to slightly elliptical, 2.0– 3.3 mm wide (average 2.6 mm, n=66, σ=0.3), placed on anterior face, at a level with coenosteum surface or slightly raised from it. There are 14–21 dactylotomes per cyclosystem (mode 18, n=66). They are 0.1–0.2 mm wide and occupy about 1/3 of gastropore tube total heigth. Pseudosepta concave with maximum width of 0.2–0.3 mm. Abcauline margin of cyclosystems bears a slightly concave lid as a result of fusion of two or more pseudosepta ( Fig. 6b View FIGURE 6 ). Far end of lid 0.5–1.5 mm wide and proximal end 0.8–1.1 mm wide. An additional lid can develop in adcauline margin of cyclosystem, facing the initial one. Lid can also be forked due to presence of a dactylotome. One or two round nematopores 40–67 µm in diameter may be present on lids as well, or on pseudosepta and cyclosystem wall.

Gastropores round, 0.8–0.9 mm wide. Gastropore tube double-chambered and about 1.6 mm deep, with gastropore ring constriction almost at bottom of tube, resulting in a very shallow basal chamber ( Fig. 6b View FIGURE 6 ).

Ampullae placed inside cyclosystem wall and lid. Male ampullae occupy interior of lid and surround cyclosystem in a semicircle centred at lid, with three or four slightly sunken efferent pores on cyclosystem wall ( Fig. 6b View FIGURE 6 ). Female ampullae occupy interior of lid and extend backwards forming a conspicuous bump ( Fig. 6a View FIGURE 6 ). Female efferent pore at base of lid and opens towards interior of gastropore tube ( Fig. 6d, e View FIGURE 6 ).

Discussion. Specimens from study area coincide with Cairns’ (1983a) description of C. formosa   in all characters, except the diameter of cyclosystems, which is larger in specimens from the study area. This could be due to variability within the species. Cairns (1983a) only described female specimens of C. formosa   , but in 2015 he established the ampullar configuration for this species as B1-C1 (B1=female efferent pore beneath lid; C1=male ampullae surround cyclosystem and efferent pores apical), which coincides with the sexual characteristics of the specimens described here.

Crypthelia formosa   is the only species of the genus found hitherto in the SWA. Previous records are from Cairns (1983a) based on specimens from Scotia Arc, Burdwood Bank and South Georgia, and from Río Iglesias et al. (2012), based on specimens collected from Patagonia, from 42° S to 48° S within a depth range of 200–1500 m (specific depth not informed). In the Antarctic zone there are only two other species, also present in New Zealand: C. fragilis   and C. studeri   (see Bax and Cairns 2014). Specimens from the study area differ from C. fragilis   in having a larger cyclosystem and gastropore diameter and higher number of dactylotomes per cyclosystem, and they differ from C. studeri   in cyclosystem shape, often irregular in C. studeri   , and in pseudosepta width, much lower in C. studeri   . Besides, neither C. fragilis   nor C. studeri   develop an additional lid, as occurs in specimens from study area and in C. formosa   . Identification of C. formosa   specimens from off Mar del Plata provides an extension of the known distribution of this species within SWA.














Crypthelia formosa Cairns, 1983a

Bernal, M. C., Cairns, S. D., Penchaszadeh, P. E. & Lauretta, D. 2021

Crypthelia formosa

Cairns, S. D. 2015: 310
Bax, N. & Cairns, S. D. 2014: 107
Rio Iglesias, J. L. & Acosta & Yepes J. & Cristobo Rodriguez, J. & Martinez Portela, J. & Parra Descalzo, S. & Tel E. & Vinas Dieguez, L. & Munoz Recio, A. & Vilela Perez, R. & Jimenez, E. E. & Ibarrola, T. P. & Rios Lopez, P. & Almon Pazos, B. & Blanco Perez, R. & Murillo Perez, J. & Polonio Povedano, V. & Fernandez Feijoo, J. & Cabanas, J. M. & Gago Pineiro, J. M. & Gonzalez-Nuevo Gonzales, G. & Cabrero Rodriguez, A. & Besada Montenegro, M. V. & Schultze Prado, F. & Franco Hernandez, A. & Bargiela Barros, J. & Garcia Blanco, X. 2012: 191
Cairns, S. D. 1983: 136
Cairns, S. D. 1983: 431