Halecium delicatulum Coughtrey, 1876

Schuchert, Peter, 2005, Taxonomic revision and systematic notes on some Halecium species (Cnidaria, Hydrozoa), Journal of Natural History 39 (8), pp. 607-639 : 629-631

Halecium delicatulum Coughtrey, 1876

( Figure 12 ) Halecium delicatulum Coughtrey 1876, p 26 , Plate 3 Figures 4 , 5 ; Ralph 1958,

p 334, Figures 11e , h–n, 12a–p, synonymy; Vervoort 1972, p 27, Figures 4 , 5 ;

Watson 1973, p 166; Millard 1975, p 145, Figure 47F–L; Stepanjants 1979, p 105,

Plate 20, Figure 4A, B ; Rees and Vervoort 1987, p 25, Figure 5 , synonymy;

Genzano 1990, p 38, Figure 2–5 ; Hirohito 1995, p 20, Figure 5 a–c, Plate 1 Figure c; Migotto 1996, p 30, Figure 6d, e ; Vervoort and Watson 2003, p 88, Figures 15 I–L, 16A–E.

Halecium gracile Bale 1888, p 759 , Plate 14, Figures 1–3 .

[Not Halecium gracile Verrill 1874 .]

Halecium parυulum Bale 1888, p 760, Plate 14 Figures 4 , 5 ; Millard 1957, p 189, Figure 4A ; Vervoort 1959, p 227, Figure 7 .

Halecium flexile Allman 1888, p 11 , Plate 5 Figure 2 .

Not Halecium flexile: Fraser 1914, p 165 , Plate 20 Figure 71; Fraser 1937, p 104, Plate 21 Figure 111; Fraser 1944, p 192, Figure 169 [5 Halecium fraseri Ralph 1958 ].

Halecium balei Fraser 1911, p 46 , new name.

Halecium flexile var. japonica Leloup 1938, p 4 , Figure 1 .

Not Halecium delicatulum: Leloup 1960, p 218 , Figure 1B .

Not Halecium parυulum f. macrothecum Leloup 1960, p 218, Figure 1B .

Not Halecium parυulum var. magnum Millard 1957, p 190 , Figure 4 B–O.

Material examined

MHNG INVE 26669, New Zealand, Wellington, Te Raekaihau, coll. 1994 by P. Schuchert, fertile female.

Characteristics

Colony 1.5 cm, monosiphonic, morphology and dimensions of trophosome indistinguishable from H. mediterraneum described above. Female gonotheca slightly larger (1 mm), body more rounded, distal opening on a distinct protrusion, notch of opening narrower, 20– 22 eggs, egg diameter about 0.09–0.12 mm. Colour of colonies according to Coughtrey (1876) pale and transparent.

Distribution

Reportedly cosmopolitan ( Peña Cantero and García Carrascosa 2002), not in Arctic regions (see below). Type localities: Halecium delicatulum, Dunedin Harbour , New Zealand; Halecium gracile, Port Stephens and Port Jackson , Australia; Halecium parυulum, Bondi Bay, Sydney, Australia; Halecium flexile, Marion Island, southern Indian Ocean; Halecium flexile var. japonica, Sagami Bay , Japan.

Remarks

See discussion under H. mediterraneum . Halecium delicatulum has been reported to occur in nearly all oceans and is thus considered cosmopolitan ( Peña Cantero and García Carrascosa 2002). The descriptions of some records, however, are quite distinct and suggest that some belong to different species. Halecium parυulum var. magnum Millard, 1957 forms large, stiff, highly polysiphonic colonies. The dimensions of the hydrothecae and gonothecae are significantly larger. The female gonothecae have a different shape and contain a reduced hydranth. Mature gonothecae have only three to four large eggs. Because both morphotypes occur sympatrically in South Africa, Halecium parυulum var. magnum should be regarded as specifically distinct from H. delicatulum .

The infertile material from the Arctic Sea described by Leloup (1960) is very unlikely to be H. delicatulum . Better guesses may be H. minutum Broch, 1903 or H. textum Kramp, 1911 (see below).

Figures

Figure 1. Halecium scutum Clark, 1877; colony silhouettes of material from The Faroes. (A) MHNG INVE 33550; (B) BIOFAR station 699; (C) BIOFAR station 459. Scale bar: 2 cm.

Figure 2. Halecium scutum Clark, 1877. (A) From BIOFAR 699; (B) BIOFAR 556; (C–E) Holsteinsborg, Greenland; (F, G) Augpilagtoq, Greenland. (A–C, F) Segments from monosiphonic parts with primary and sometimes secondary hydrothecae (scale bar: 0.2 mm); (D) female gonotheca in side view, eggs stippled (scale bar: 0.2 mm); (E) higher magnification of gonothecal opening, side view (scale bar: 0.1 mm); (G) male gonotheca (same scale bar as D).

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 4. Halecium halecinum (Linnaeus, 1758). (A–C) Segments of monosiphonic parts, with secondary hydrothecae, note length variation of internodes, BIOFAR station 350, 205 and 351; (D) BIOFAR 351, female gonotheca in side view; (E) as in (D), but seen from anterior side, note bipartite hydrotheca; (F) BIOFAR 597, male gonotheca. Scale bar: 0.2 mm.

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 7. Halecium lankesterii (Bourne, 1890); after material from Brittany. (A) Colony silhouette (scale bar: 5 mm); (B) part of stem (scale bar: 0.2 mm); (C) lower part of stem with characteristic ahydrothecate segments with constriction in middle (scale bar: 0.1 mm); (D) hydrothecate segment (same scale bar as C); (E) female gonotheca in oblique view, shown without hydranths (scale bar: 0.2 mm); (F) female gonotheca seen from anterior side (same scale bar as E); (G) lateral view of female gonotheca, higher magnification of opening (scale bar: 0.1 mm).

Figure 11. Halecium mediterraneum Weismann, 1883; after preserved Mediterranean material. (A) Silhouettes of three fertile colonies showing variability of growth (scale bar: 1 cm); (B) branching pattern of stem (scale bar: 0.2 mm); (C) distal part with geniculate segments (same scale bar as B); (D) primary and secondary hydrotheca (scale bar: 0.1 mm); (E–G) female gonothecae (same scale bar as B), (E) in frontal view and with broad opening, (F) in side view, (G) most commonly found opening size; (H–K) male gonothecae (same scale bar as B), (H) with soft tissue, (I) empty, (K) in side view; (L) empty female gonotheca cut apart to demonstrate secondary capsule within outer capsule (scale bar: 0.1 mm); (M) range of variation of distal openings of female gonothecae (same scale bar as L).

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 15. Halecium corrugatissimum Trebilcock, 1928. (A) Part of stem with hydrotheca and secondary hydrothecae (scale bar: 0.1 mm); (B) same as (A), note distance of hydrotheca from side-branch and apophysis; (C, D) female gonothecae with eggs (stippled) (scale bar: 0.2 mm); (E, F) male gonothecae (same scale bar as C, D).