Halecium textum Kramp, 1911

Schuchert, Peter, 2005, Taxonomic revision and systematic notes on some Halecium species (Cnidaria, Hydrozoa), Journal of Natural History 39 (8), pp. 607-639 : 631-632

Halecium textum Kramp, 1911

( Figure 13 )

Halecium textum Kramp 1911, p 368 , Plate 21 Figures 5 , 6 ; Schuchert 2001, p 85, Figure 71A–G, 72A, B.

Halecium tenellum: Jäderholm 1909, p 27 , Plate 4 Figure 12 ; Fraser 1944, p 201, Figure 179 [not Halecium tenellum Hincks 1861 ].

In part Halecium tenellum: Broch 1918, p 46 , Figures 20, 21; Kramp 1932, p 19; Kramp 1938, p 8; Kramp 1943, p 32.

? Halecium undulatum Billard 1922, p 137 , Figure 3 .

Halecium undulatum : in part Calder 1970, p 1510, Plate 2 Figures 5–8 , not 9 [?5 H. minutum ]; Hamond 1957, p 304, Figures 12 , 13 ; Cornelius 1995, p 198, Figure 70.

Material examined

MHNG INVE 33592 and 33574 ( BIOICE collection), 65.78 ° N, 14.22 ° W, Iceland, 28–60 m, 24 July 1991 , on bryozoan and on Sertularella polyzonias , with female gonothecae. BIOFAR station 402, 62.10 ° N, 8.14 ° W, The Faroes , 121 m, 30 May 1989 . BIOFAR station 554, 61.94 ° N, 6.50 ° W, The Faroes , 62 m, 22 September 1989 , on hydroid.

Description

Colonies reaching 2 cm in height, stems irregularly branched, polytomies frequent, branches not in one plane. Larger colonies form a tangled mass. Branches curving sharply upwards, with irregularly occurring nodes. Perisarc strongly undulated or corrugated over stretches, but smooth stretches can also occur. Hydrotheca on hydrophore of about equal length as hydrothecal depth. Hydrotheca diameter at base 0.1 mm, depth 30–50 mm, upper part distinctly everted or even rolled-in, diaphragm fine, desmocytes present. Below diaphragm frequently a pseudo-diaphragm, variable in form and position, either formed as a horizontal or oblique annular thickening or as a mere process at the origin of the apophysis. Gonothecae borne on branches, dioecious. Female gonotheca about 1 mm long, oblong, in side view only half as thick, narrow truncated end with oval aperture. Male gonotheca slightly smaller, spindle-shaped, not much flattened, shape somewhat variable, gonad fills gonotheca nearly completely (after Schuchert 2001).

Distribution

Boreal-arctic species; known from Greenland, north-eastern Canada, western and eastern Iceland, Faroes. Some records of H. undulatum from the British Isles, the North Sea, Sweden, and Norway could also be H. textum . Type locality: Maroussia, eastern Greenland, 160–180 m ( Kramp 1911).

Remarks

This species has recently been re-described by Schuchert (2001) and several records previously attributed to H. tenellum or H. undulatum could be referred to it. The newly examined material from eastern Iceland, from where it has not been recorded so far, is especially notable for the strongly corrugated perisarc ( Figure 14A, B ).

Figures

Figure 3. Halecium halecinum (Linnaeus, 1758); colony silhouettes, note variation of shapes. (A) Canary Islands; (B) The Faroes (BIOFAR station 111); (C) The Faroes (BIOFAR station 554). Scale bar: 2 cm.

Figure 5. Halecium beanii (Johnston, 1838). (A, D) From Roscoff; (B, C, E–H) from The Faroes. (A–C) Colony silhouettes (scale bar: 1 cm); (D–F) subterminal portions of branches (scale bar: 0.2 mm); (G) female gonotheca, middle one seen from side of hydrothecae, right one shown with developing embryos (scale bar: 0.2 mm); (H) male gonotheca (same scale bar as G).

Figure 6. Halecium beanii (Johnston, 1838). (A–D) After material from South Africa; (E–F) after material from New Zealand. (A) Two internodes (scale bar: 0.2 mm); (B) female gonotheca in oblique view (scale bar: 0.2 mm); (C) cross-section of female gonothecae in about the middle of its height, note polygonal outline (same scale bar as B); (D) three male gonothecae, note variability (same scale bar as B); (E) two internodes (same scale bar as A); (F) female gonotheca (same scale bar as B).

Figure 12. Halecium delicatulum Coughtrey, 1876, after preserved material from New Zealand. (A) Segment with primary and secondary hydrotheca; (B) female gonotheca, broad view. Scale bar: 0.1 mm.

Figure 13. Halecium textum Kramp, 1911; after MHNG INVE 33592, Iceland. (A, B) Hydrothecae and internodes, note strong corrugation (scale bar: 0.1 mm); (C) part of colony with three female gonothecae, eggs stippled (scale bar: 0.5 mm).

Figure 14. Halecium banyulense Motz-Kossowska, 1911, after MHNG INVE 34237. (A) Colony silhouette (scale bar: 1 cm); (B) internode from monosiphonic part (scale bar: 0.2 mm); (C) hydrothecae with regenerated hydrothecae of second and higher degree (scale bar: 0.1 mm); (D) female gonotheca, drawn opaque to visualize radiating depressions (same scale bar as B).