Halecium incertus Naumov & Stepanjants 1962
Halecium incertus Naumov & Stepanjants 1962 (Figs 6–7) Halecium incertus Naumov & Stepanjants, 1962: 98, fig. 18; Stepanjants, 1979: 107, pl. 20 fig. 7 A–V; Vervoort & Watson, 2003: 86; Peña Cantero, 2004: 769; Peña Cantero & Gili, 2006: 766. Halecium dufresnae Millard, 1977: 8, fig....
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Online Access: | https://dx.doi.org/10.5281/zenodo.4630885 https://zenodo.org/record/4630885 |
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ftdatacite:10.5281/zenodo.4630885 |
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openpolar |
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Biodiversity Taxonomy Animalia Cnidaria Hydrozoa Leptothecata Haleciidae Halecium Halecium incertus |
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Biodiversity Taxonomy Animalia Cnidaria Hydrozoa Leptothecata Haleciidae Halecium Halecium incertus Peña Cantero, Álvaro L. Halecium incertus Naumov & Stepanjants 1962 |
topic_facet |
Biodiversity Taxonomy Animalia Cnidaria Hydrozoa Leptothecata Haleciidae Halecium Halecium incertus |
description |
Halecium incertus Naumov & Stepanjants 1962 (Figs 6–7) Halecium incertus Naumov & Stepanjants, 1962: 98, fig. 18; Stepanjants, 1979: 107, pl. 20 fig. 7 A–V; Vervoort & Watson, 2003: 86; Peña Cantero, 2004: 769; Peña Cantero & Gili, 2006: 766. Halecium dufresnae Millard, 1977: 8, fig. 2 A–D; 1979: 138; Branch & Williams, 1993: 11, fig.; Vervoort & Watson, 2003: 85. Halecium macrocaulus Watson, 2008: 173 –174, fig. 9 A–F. Not Halecium incertus — Peña Cantero, 2008: 454 –455, fig. 1 b; 2009: 1747; 2012: 857 (= Halecium pseudoincertus sp. nov. ). Material examined. Holotype of Halecium incertus , ZIRAS, “Ob” II SAE , Stn 204 , 30–02–1957, 65° 59,2S 57 °08’ 8 E (Enderby Land), 270 m, three stem fragments, 42, 32 and 30 mm long, with gonothecae. Holotype of Halecium macrocaulus , BANZARE , Stn 107 , 66° 45 'S 62 °03'E (Mawson Coast), 210 m, one microslide, NMV F 147467, one stem fragment, c. 24 mm long, with gonothecae. German Antarctic Expedition Polarstern XXI/ 2 : Stn PS 65 /019 , one stem, c. 195 mm high, with gonothecae. Diagnosis. Strongly polysiphonic, irregularly branched stems, up to 300 mm high. Branches originating from hydrophore of primary hydrotheca. Hydrothecae alternately arranged in one or two planes. Hydrotheca at the end of short, adnate hydrophore provided with oblique pseudodiaphragm. Hydrotheca distinctly widening distally; rim slightly everted. Adcauline hydrothecal wall free; distinctly larger than abcauline one. Hydrothecal aperture slightly directed downwards. Up to one secondary hydrotheca present. Male gonoteca oval, elongated with distal, shallow groove. Female gonotheca flattened, terebratulid brachiopod-shaped; abcauline wall longer. Aperture at distal part. With acrocyst (one embryo). Cnidome consisting of isorhizas, larger microbasic euryteles, smaller microbasic euryteles and microbasic mastigophores. Description (type material of H. incertus ). Three stem fragments, c. 42, 32 and 30 mm long. 42 -mm-long fragment corresponding to a basal stem fragment, strongly polysiphonic, c. 3 mm in diameter, and provided with a primary branch, strongly polysiphonic too. Branches divided into internodes by alternately arranged, slightly oblique nodes. Hydrothecae on adnate hydrophores (Fig. 6 A–D); ratio between adcauline length of hydrophore and diameter at diaphragm 1.2–1.5. Hydrotheca low (Fig. 6 A–D), distinctly widening from diaphragm upwards. Adcauline wall distinctly larger than abcauline one (Fig. 6 A, D). Adcauline hydrothecal wall free to internode (Fig. 6 A–D). Hydrothecal aperture slightly directed downwards. Hydrothecal rim slightly everted (Fig. 6 A). Up to one secondary hydrotheca present (Fig. 6 A). An oblique, upwards directed pseudodiaphragm present (Fig. 6 A,D). Two female gonothecae present, arising from hydrophore of primary hydrotheca. Gonotheca fusiform, terebratulid brachiopod-shaped, with one side shorter (Fig. 6 E). Measurements (in µm). Hydrothecae : diameter at aperture 260–300, diameter at diaphragm 230–250, height 35–50. Internodes : length 550–700, diameter 210–300. Gonothecae : height c. 1350, maximum diameter c. 470. Cnidome : isorhizas [range 19.0– 21.5 x 6.0–8.0, mean 20.5 ± 0.7 x 7.2 ± 0.6 (n= 10); ratio, range 2.6–3.3, mean 2.9 ± 0.2 (n= 10)], larger microbasic euryteles?, very abundant [range 15.5 –18.0 x 6.0–8.0, mean 16.4 ± 0.7 x 7.3 ± 0.7 (n= 10); ratio, range 2.0– 2.7, mean 2.3 ± 0.2 (n= 10)], smaller microbasic euryteles [range 7.5 –8.0 x 4.0, mean 7.8 ± 0.2 x 4.0±0.0 (n= 10); ratio, range 1.9 –2.0, mean 2.0± 0.1 (n= 10)], and microbasic mastigophores [range 8.0– 8.5 x 2.0– 2.5, mean 8.3 ± 0.2 x 2.3 ± 0.2 (n= 10); ratio, range 3.2–4.3, mean 3.7 ± 0.4 (n= 10)]. Description (type material of H. macrocaulus ). “Thickest fragments (stem or major branches) 6 mm wide at base and 200 mm long; branching profuse and irregular, originally all around stem” (Watson 2008: 173). Apparently, branching alternate at every third hydrotheca in the material examined. Branches originating just below cauline hydrothecae. Primary branches in turn giving rise to one or two secondary branches. Stem and branches divided into internodes by little marked, alternately arranged, oblique nodes (Fig. 6 F–H). Hydrothecae alternately arranged in two planes. Hydrothecae resting on adnate hydrophores (Fig. 6 F–H); ratio between adcauline length of hydrophore and diameter at diaphragm c. 1.0. Hydrotheca low and free, oblique, directed downwards (Fig. 6 F–H). Rim everted. Hydrotheca strongly widening distally, much more at adcauline side, forming a distinct concavity (Fig. 6 F). Adcauline hydrothecal side completely free and reaching next internode (Fig. 6 F–H). Adcauline hydrothecal side higher than abcauline one (Fig. 6 F–H). A distinct pseudodiaphragm present, much more marked towards adcauline side (Fig. 6 F). Gonothecae originating directly from lateral of hydrophore (i.e., neither pedicel nor apophysis present) (Fig. 6 G). Gonotheca inverted pear-shaped, strongly narrowing at base and broadly rounded at distal part (Fig. 6 I). Maximum diameter at distal fifth. Measurements (in µm). Hydrothecae : diameter at aperture 250–270, diameter at diaphragm 220–240, height abcauline wall 30–50, height adcauline wall 50–80. Hydrophore : adcauline length 220–250. Internodes : length 630–800, diameter 250–300. Gonothecae : height c. 1420, maximum diameter c. 800. Cnidome : heteronemes (only one type could be observed since observations were made on a microslide) 15–17.5 x 5 [19–24 x 7–9 according to Watson (2008)]. Description (PS 65 / 19). One branched, strongly polysiphonic stem c. 195 mm high. Stem giving rise to several strongly-developed, polysiphonic, primary branches which, in turn, form polysiphonic secondary ones. Polysiphonic branches giving rise to lower-order branches, most monosiphonic, but some slightly polysiphonic basally. Overall, up to five-order branching observed. Branches divided into internodes by alternately arranged, slightly oblique nodes. Hydrothecae resting on adnate hydrophores; ratio between adcauline length of hydrophore and diameter at diaphragm c. 1.3 (Fig. 7 A–C). Hydrotheca low, distinctly widening from diaphragm upwards (Fig. 7 A). Adcauline wall slightly larger than abcauline one (Fig. 7 A, B). Adcauline hydrothecal wall free to internode (Fig. 7 A). Hydrothecal aperture directed downwards. Sometimes a secondary hydrotheca present (Fig. 7 C). An oblique, usually well-marked pseudodiaphragm present (Fig. 7 A, C). Female gonothecae present, arising from hydrophore. Gonotheca flattened; terebratulid brachiopod-shaped, with one side shorter (Fig. 7 E, F), in lateral view, when immature, and fusiform when mature. In frontal view, gonotheca more or less triangular (Fig. 7 D, G). Measurements (in µm). Hydrothecae : diameter at aperture 245–250, diameter at diaphragm 190–220, height 35–50. Gonothecae : height 1300–1400, maximum diameter c. 500 (lateral view) and 700–780 (frontal view). Cnidome : innumerous isorhizas [range 17.5 –19.0 x 7.0–8.0, mean 18.3 ± 0.5 x 7.2 ± 0.3 (n= 10); ratio, range 2.4–2.7, mean 2.6 ± 0.1 (n= 10)], larger microbasic euryteles? [range 13.0–14.0 x 6.5–7.5, mean 13.5 ± 0.4 x 7.1 ± 0.4 (n= 5); ratio, range 1.8 –2.0, mean 1.9 ± 0.1 (n= 5)], smaller microbasic euryteles [range 6.0– 7.5 x 3.0– 3.5, mean 6.7 ± 0.4 x 3.4 ± 0.2 (n= 10); ratio, range 1.9–2.2, mean 2.0± 0.1 (n= 10)], and microbasic mastigophore (7.5–8 x 2 –2.5). Remarks. Stepanjants (1979) described two types of gonothecae, probably male and female. Putative male gonotheca oval, elongated with a distal, shallow groove. Female gonotheca pear-shaped, flattened, and with external acrocyst. In the material from PS 65 / 19 there are gonothecae with acrocyst where embryo is completing its development (Fig. 7 D) and others where embryo is little developed and still within the gonotheca with the surrounding acrocyst (Fig. 7 E–G). Apparently, shorter side deploys to allow embryo and acrocyst to exit (Fig. 7 D). Naumov & Stepanjants (1962) characterized this species by the structure of the hydrotheca. They indicated that the “obliquely cut aperture with turned out edges and the presence of two diaphragms in the hydrotheca separate the new species from all the known species of the genus Halecium ”. According to these authors, the species has stems “irregularly ramified in several planes”, “with primary and secondary branches polysiphonic”. The pseudodiaphragm is oblique. Interestingly, Naumov & Stepanjants (1962) also indicated that, “considering the type of ramification, the structure of the branches and the disposal of the hydrothecae, our species appear to be related to H. arboreum Allman ”. This clearly points to a colonial structure as that found in the material here assigned to H. incertus . Stepanjants (1979) also characterized the species by having very large colonies with thick and polysiphonic stems irregularly branched repeatedly in several planes. She also indicated that young colonies have a more ordered branching: primary branches alternately arranged, second-order ones in different planes. Millard (1977) described as Halecium dufresnae a new species that agrees in every detail with H. incertus and, in fact, Stepanjants (1979) already considered this species conspecific with H. incertus . Millard’s (1977) material also has thick fascicled stem (up to 245 mm high), branching and re-branching irregularly, but mainly in one plane. Although it has not been possible to re-describe the general appearance of the colony of H. macrocaulus from the material examined, according to Watson’s (2008) description it is clear that H. macrocaulus has robust, polysiphonic and much branched stems. In addition, although Watson (2008) indicated that forks arise from within a hydrotheca, in the material examined here I found only branches originating just below the cauline hydrothecae. Watson (2008: 173) also indicated the presence of a “septum (false diaphragm) of perisarc passing diagonally through hydrophore from near junction of diaphragm with abcauline wall to adcauline wall”. This “false diaphragm” clearly corresponds with a pseudodiaphragm as it has been unequivocally demonstrated by examining the holotype material of H. macrocaulus (cf. Fig. 6 F). Halecium macrocaulus is undistinguishable from H. incertus and it is considered here conspecific with Naumov & Stepanjants’ species. They agree in colony structure, with thick stems profusely and irregularly branched, shape and size of hydrotheca, presence of pseudodiaphragm, sessile hydrophores, and size of nematocysts. The single difference concerns the presence of acrocyst in H. incertus , not described for H. macrocaulus . However, this could be explained by the fact that the gonothecae described for H. macrocaulus are either male or female but immature. As it has been shown above, in H. incertus , it is possible to find in the same colony gonothecae with acrocyst, where an embryo is completing its development, together with others where an embryo is little developed and still within the gonotheca with the surrounding acrocyst. The shape of the gonotheca of H. macrocaulus [Fig. 6 I; see also Figure 9 B by Watson (2008: 174)] is identical to that I found in H. incertus from Bouvet (cf. Fig. 7 D, G). It seems clear, from the above-shown descriptions that H. incertus is characterised by having large (up to 300 mm high), thick, polysiphonic stems giving rise to also polysiphonic, lower-order branches in one or several planes. Consequently, I conclude that the material ascribed to H. incertus by Peña Cantero (2008, 2009, 2012) belongs to a different, described below, new species to science, Halecium pseudoincertus sp. nov. Ecology and distribution. Halecium incertus has been found at depths from 15 (Stepanjants 1979) to 693 m (Branch & Williams 1993), on rock (Stepanjants 1979; Branch & Williams 1993), and gravel and mud (Stepanjants 1979). Gonothecae in April (Millard 1977; Stepanjants 1979), November (Peña Cantero & Gili 2006), and from December to February (Stepanjants 1979). Halecium incertus seems to have an Antarctic –Kerguélen distribution (Peña Cantero & Gili 2006), having been found in both Antarctic and sub-Antarctic waters. In the latter, it is known from off Crozet (Millard 1977; Stepanjants 1979), Kerguélen (Stepanjants 1979) and the Marion and Prince Edward islands area (Branch & Williams 1993). In Antarctic waters, it is known from the Sodruzestva Sea (Naumov & Stepanjants 1962), off the Amery Ice Shelf (Stepanjants 1979), and off Mawson Coast (Watson 2008 as H. macrocaulus ), in East Antarctica, and off Bouvet (Peña Cantero & Gili 2006). : Published as part of Peña Cantero, Álvaro L., 2014, Revision of the Antarctic species of Halecium Oken, 1815 (Cnidaria, Hydrozoa, Haleciidae), pp. 243-280 in Zootaxa 3790 (2) on pages 256-261, DOI: 10.11646/zootaxa.3790.2.2, http://zenodo.org/record/226890 : {"references": ["Naumov, D. V. & Stepanjants, S. D. (1962) Hydroida (Thecaphora) collected by the Soviet Antarctic Expedition on the M / V Ob in antarctic and subantarctic waters. In: Biological results of the Soviet Antarctic Expedition, 1955 - 1958, 1. Issledovaniya Fauny Morei, 1 (9), 68 - 106.", "Stepanjants, S. D. (1979) Hydroids of the antarctic and subantarctic waters. In: Biological results of the Soviet Antarctic Expedition, 6. Issledovaniya Fauny Morei, 20 (30), 1 - 200, pls 1 - 25. [in Russian]", "Vervoort, W. & Watson, J. E. (2003) The Marine Fauna of New Zealand: Leptothecata (Cnidaria: Hydrozoa) (Thecate Hydroids). NIWA Biodiversity Memoir, 119, 1 - 538, figs. 1 - 108.", "Pena Cantero, A. L. (2004) How rich is the deep-sea Antarctic benthic hydroid fauna? Polar Biology, 27, 767 - 774. http: // dx. doi. org / 10.1007 / s 00300 - 004 - 0654 - 9", "Pena Cantero, A. L. & Gili, J. M. (2006) Benthic hydroids (Cnidaria, Hydrozoa) from off Bouvet Island (Antarctic Ocean). Polar Biology, 29, 764 - 771. http: // dx. doi. org / 10.1007 / s 00300 - 006 - 0113 - x", "Millard, N. A. H. (1977) Hydroids from the Kerguelen and Crozet shelves, collected by the cruise MD. 03 of the Marion-Dufresne. Annals of the South African Museum, 73 (1), 1 - 47.", "Branch, M. L. & Williams, G. C. (1993) The Hydrozoa, Octocorallia and Scleractinia of subantarctic Marion and Prince Edward Islands: illustrated keys to the species and results of the 1982 - 1989 University of Cape Town surveys. South African Journal of Antarctic Research, 23 (1 - 2), 3 - 24.", "Watson, J. E. (2008) Hydroids of the BANZARE expeditions, 1929 - 1931: the family Haleciidae (Hydrozoa, Leptothecata) from the Australian Antarctic Territory. Memoirs of the Museum of Victoria, 65, 165 - 178.", "Pena Cantero, A. L. (2008) Benthic hydroids (Cnidaria: Hydrozoa) from the Spanish Antarctic expedition Bentart 95. Polar Biology, 31, 451 - 464. http: // dx. doi. org / 10.1007 / s 00300 - 007 - 0371 - 2"]} |
format |
Text |
author |
Peña Cantero, Álvaro L. |
author_facet |
Peña Cantero, Álvaro L. |
author_sort |
Peña Cantero, Álvaro L. |
title |
Halecium incertus Naumov & Stepanjants 1962 |
title_short |
Halecium incertus Naumov & Stepanjants 1962 |
title_full |
Halecium incertus Naumov & Stepanjants 1962 |
title_fullStr |
Halecium incertus Naumov & Stepanjants 1962 |
title_full_unstemmed |
Halecium incertus Naumov & Stepanjants 1962 |
title_sort |
halecium incertus naumov & stepanjants 1962 |
publisher |
Zenodo |
publishDate |
2014 |
url |
https://dx.doi.org/10.5281/zenodo.4630885 https://zenodo.org/record/4630885 |
long_lat |
ENVELOPE(-94.063,-94.063,56.565,56.565) ENVELOPE(71.000,71.000,-69.750,-69.750) ENVELOPE(3.358,3.358,-54.422,-54.422) ENVELOPE(3.358,3.358,-54.422,-54.422) ENVELOPE(40.562,40.562,63.490,63.490) ENVELOPE(63.000,63.000,-68.000,-68.000) |
geographic |
Antarctic The Antarctic East Antarctica Kerguelen Australian Antarctic Territory New Zealand Antarctic Ocean Amery Amery Ice Shelf Bouvet Bouvet Island Pena Mawson Coast |
geographic_facet |
Antarctic The Antarctic East Antarctica Kerguelen Australian Antarctic Territory New Zealand Antarctic Ocean Amery Amery Ice Shelf Bouvet Bouvet Island Pena Mawson Coast |
genre |
Amery Ice Shelf Antarc* Antarctic Antarctic Ocean Antarctica Bouvet Island East Antarctica Enderby Land Ice Shelf Prince Edward Islands |
genre_facet |
Amery Ice Shelf Antarc* Antarctic Antarctic Ocean Antarctica Bouvet Island East Antarctica Enderby Land Ice Shelf Prince Edward Islands |
op_relation |
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op_rights |
Open Access info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.5281/zenodo.4630885 https://doi.org/10.11646/zootaxa.3790.2.2 https://doi.org/10.5281/zenodo.226896 https://doi.org/10.5281/zenodo.226897 https://doi.org/10.5281/zenodo.226899 https://doi.org/10.5281/zenodo.4630633 https://d |
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ftdatacite:10.5281/zenodo.4630885 2023-05-15T13:22:13+02:00 Halecium incertus Naumov & Stepanjants 1962 Peña Cantero, Álvaro L. 2014 https://dx.doi.org/10.5281/zenodo.4630885 https://zenodo.org/record/4630885 unknown Zenodo http://zenodo.org/record/226890 http://publication.plazi.org/id/C25BFF98294DFF8F2C3E185B3F31FFAC http://treatment.plazi.org/id/039D5126FFAEFFB51898FBE619C893CE http://zoobank.org/BE6B199C-6E81-478A-8AC9-EB674B85FA35 https://zenodo.org/communities/biosyslit https://dx.doi.org/10.11646/zootaxa.3790.2.2 http://zenodo.org/record/226890 http://publication.plazi.org/id/C25BFF98294DFF8F2C3E185B3F31FFAC https://dx.doi.org/10.5281/zenodo.226896 https://dx.doi.org/10.5281/zenodo.226897 https://dx.doi.org/10.5281/zenodo.226899 https://dx.doi.org/10.5281/zenodo.4630633 http://treatment.plazi.org/id/039D5126FFAEFFB51898FBE619C893CE http://zoobank.org/BE6B199C-6E81-478A-8AC9-EB674B85FA35 https://dx.doi.org/10.5281/zenodo.4630884 https://zenodo.org/communities/biosyslit Open Access info:eu-repo/semantics/openAccess Biodiversity Taxonomy Animalia Cnidaria Hydrozoa Leptothecata Haleciidae Halecium Halecium incertus Taxonomic treatment article-journal Text ScholarlyArticle 2014 ftdatacite https://doi.org/10.5281/zenodo.4630885 https://doi.org/10.11646/zootaxa.3790.2.2 https://doi.org/10.5281/zenodo.226896 https://doi.org/10.5281/zenodo.226897 https://doi.org/10.5281/zenodo.226899 https://doi.org/10.5281/zenodo.4630633 https://d 2022-02-08T13:29:49Z Halecium incertus Naumov & Stepanjants 1962 (Figs 6–7) Halecium incertus Naumov & Stepanjants, 1962: 98, fig. 18; Stepanjants, 1979: 107, pl. 20 fig. 7 A–V; Vervoort & Watson, 2003: 86; Peña Cantero, 2004: 769; Peña Cantero & Gili, 2006: 766. Halecium dufresnae Millard, 1977: 8, fig. 2 A–D; 1979: 138; Branch & Williams, 1993: 11, fig.; Vervoort & Watson, 2003: 85. Halecium macrocaulus Watson, 2008: 173 –174, fig. 9 A–F. Not Halecium incertus — Peña Cantero, 2008: 454 –455, fig. 1 b; 2009: 1747; 2012: 857 (= Halecium pseudoincertus sp. nov. ). Material examined. Holotype of Halecium incertus , ZIRAS, “Ob” II SAE , Stn 204 , 30–02–1957, 65° 59,2S 57 °08’ 8 E (Enderby Land), 270 m, three stem fragments, 42, 32 and 30 mm long, with gonothecae. Holotype of Halecium macrocaulus , BANZARE , Stn 107 , 66° 45 'S 62 °03'E (Mawson Coast), 210 m, one microslide, NMV F 147467, one stem fragment, c. 24 mm long, with gonothecae. German Antarctic Expedition Polarstern XXI/ 2 : Stn PS 65 /019 , one stem, c. 195 mm high, with gonothecae. Diagnosis. Strongly polysiphonic, irregularly branched stems, up to 300 mm high. Branches originating from hydrophore of primary hydrotheca. Hydrothecae alternately arranged in one or two planes. Hydrotheca at the end of short, adnate hydrophore provided with oblique pseudodiaphragm. Hydrotheca distinctly widening distally; rim slightly everted. Adcauline hydrothecal wall free; distinctly larger than abcauline one. Hydrothecal aperture slightly directed downwards. Up to one secondary hydrotheca present. Male gonoteca oval, elongated with distal, shallow groove. Female gonotheca flattened, terebratulid brachiopod-shaped; abcauline wall longer. Aperture at distal part. With acrocyst (one embryo). Cnidome consisting of isorhizas, larger microbasic euryteles, smaller microbasic euryteles and microbasic mastigophores. Description (type material of H. incertus ). Three stem fragments, c. 42, 32 and 30 mm long. 42 -mm-long fragment corresponding to a basal stem fragment, strongly polysiphonic, c. 3 mm in diameter, and provided with a primary branch, strongly polysiphonic too. Branches divided into internodes by alternately arranged, slightly oblique nodes. Hydrothecae on adnate hydrophores (Fig. 6 A–D); ratio between adcauline length of hydrophore and diameter at diaphragm 1.2–1.5. Hydrotheca low (Fig. 6 A–D), distinctly widening from diaphragm upwards. Adcauline wall distinctly larger than abcauline one (Fig. 6 A, D). Adcauline hydrothecal wall free to internode (Fig. 6 A–D). Hydrothecal aperture slightly directed downwards. Hydrothecal rim slightly everted (Fig. 6 A). Up to one secondary hydrotheca present (Fig. 6 A). An oblique, upwards directed pseudodiaphragm present (Fig. 6 A,D). Two female gonothecae present, arising from hydrophore of primary hydrotheca. Gonotheca fusiform, terebratulid brachiopod-shaped, with one side shorter (Fig. 6 E). Measurements (in µm). Hydrothecae : diameter at aperture 260–300, diameter at diaphragm 230–250, height 35–50. Internodes : length 550–700, diameter 210–300. Gonothecae : height c. 1350, maximum diameter c. 470. Cnidome : isorhizas [range 19.0– 21.5 x 6.0–8.0, mean 20.5 ± 0.7 x 7.2 ± 0.6 (n= 10); ratio, range 2.6–3.3, mean 2.9 ± 0.2 (n= 10)], larger microbasic euryteles?, very abundant [range 15.5 –18.0 x 6.0–8.0, mean 16.4 ± 0.7 x 7.3 ± 0.7 (n= 10); ratio, range 2.0– 2.7, mean 2.3 ± 0.2 (n= 10)], smaller microbasic euryteles [range 7.5 –8.0 x 4.0, mean 7.8 ± 0.2 x 4.0±0.0 (n= 10); ratio, range 1.9 –2.0, mean 2.0± 0.1 (n= 10)], and microbasic mastigophores [range 8.0– 8.5 x 2.0– 2.5, mean 8.3 ± 0.2 x 2.3 ± 0.2 (n= 10); ratio, range 3.2–4.3, mean 3.7 ± 0.4 (n= 10)]. Description (type material of H. macrocaulus ). “Thickest fragments (stem or major branches) 6 mm wide at base and 200 mm long; branching profuse and irregular, originally all around stem” (Watson 2008: 173). Apparently, branching alternate at every third hydrotheca in the material examined. Branches originating just below cauline hydrothecae. Primary branches in turn giving rise to one or two secondary branches. Stem and branches divided into internodes by little marked, alternately arranged, oblique nodes (Fig. 6 F–H). Hydrothecae alternately arranged in two planes. Hydrothecae resting on adnate hydrophores (Fig. 6 F–H); ratio between adcauline length of hydrophore and diameter at diaphragm c. 1.0. Hydrotheca low and free, oblique, directed downwards (Fig. 6 F–H). Rim everted. Hydrotheca strongly widening distally, much more at adcauline side, forming a distinct concavity (Fig. 6 F). Adcauline hydrothecal side completely free and reaching next internode (Fig. 6 F–H). Adcauline hydrothecal side higher than abcauline one (Fig. 6 F–H). A distinct pseudodiaphragm present, much more marked towards adcauline side (Fig. 6 F). Gonothecae originating directly from lateral of hydrophore (i.e., neither pedicel nor apophysis present) (Fig. 6 G). Gonotheca inverted pear-shaped, strongly narrowing at base and broadly rounded at distal part (Fig. 6 I). Maximum diameter at distal fifth. Measurements (in µm). Hydrothecae : diameter at aperture 250–270, diameter at diaphragm 220–240, height abcauline wall 30–50, height adcauline wall 50–80. Hydrophore : adcauline length 220–250. Internodes : length 630–800, diameter 250–300. Gonothecae : height c. 1420, maximum diameter c. 800. Cnidome : heteronemes (only one type could be observed since observations were made on a microslide) 15–17.5 x 5 [19–24 x 7–9 according to Watson (2008)]. Description (PS 65 / 19). One branched, strongly polysiphonic stem c. 195 mm high. Stem giving rise to several strongly-developed, polysiphonic, primary branches which, in turn, form polysiphonic secondary ones. Polysiphonic branches giving rise to lower-order branches, most monosiphonic, but some slightly polysiphonic basally. Overall, up to five-order branching observed. Branches divided into internodes by alternately arranged, slightly oblique nodes. Hydrothecae resting on adnate hydrophores; ratio between adcauline length of hydrophore and diameter at diaphragm c. 1.3 (Fig. 7 A–C). Hydrotheca low, distinctly widening from diaphragm upwards (Fig. 7 A). Adcauline wall slightly larger than abcauline one (Fig. 7 A, B). Adcauline hydrothecal wall free to internode (Fig. 7 A). Hydrothecal aperture directed downwards. Sometimes a secondary hydrotheca present (Fig. 7 C). An oblique, usually well-marked pseudodiaphragm present (Fig. 7 A, C). Female gonothecae present, arising from hydrophore. Gonotheca flattened; terebratulid brachiopod-shaped, with one side shorter (Fig. 7 E, F), in lateral view, when immature, and fusiform when mature. In frontal view, gonotheca more or less triangular (Fig. 7 D, G). Measurements (in µm). Hydrothecae : diameter at aperture 245–250, diameter at diaphragm 190–220, height 35–50. Gonothecae : height 1300–1400, maximum diameter c. 500 (lateral view) and 700–780 (frontal view). Cnidome : innumerous isorhizas [range 17.5 –19.0 x 7.0–8.0, mean 18.3 ± 0.5 x 7.2 ± 0.3 (n= 10); ratio, range 2.4–2.7, mean 2.6 ± 0.1 (n= 10)], larger microbasic euryteles? [range 13.0–14.0 x 6.5–7.5, mean 13.5 ± 0.4 x 7.1 ± 0.4 (n= 5); ratio, range 1.8 –2.0, mean 1.9 ± 0.1 (n= 5)], smaller microbasic euryteles [range 6.0– 7.5 x 3.0– 3.5, mean 6.7 ± 0.4 x 3.4 ± 0.2 (n= 10); ratio, range 1.9–2.2, mean 2.0± 0.1 (n= 10)], and microbasic mastigophore (7.5–8 x 2 –2.5). Remarks. Stepanjants (1979) described two types of gonothecae, probably male and female. Putative male gonotheca oval, elongated with a distal, shallow groove. Female gonotheca pear-shaped, flattened, and with external acrocyst. In the material from PS 65 / 19 there are gonothecae with acrocyst where embryo is completing its development (Fig. 7 D) and others where embryo is little developed and still within the gonotheca with the surrounding acrocyst (Fig. 7 E–G). Apparently, shorter side deploys to allow embryo and acrocyst to exit (Fig. 7 D). Naumov & Stepanjants (1962) characterized this species by the structure of the hydrotheca. They indicated that the “obliquely cut aperture with turned out edges and the presence of two diaphragms in the hydrotheca separate the new species from all the known species of the genus Halecium ”. According to these authors, the species has stems “irregularly ramified in several planes”, “with primary and secondary branches polysiphonic”. The pseudodiaphragm is oblique. Interestingly, Naumov & Stepanjants (1962) also indicated that, “considering the type of ramification, the structure of the branches and the disposal of the hydrothecae, our species appear to be related to H. arboreum Allman ”. This clearly points to a colonial structure as that found in the material here assigned to H. incertus . Stepanjants (1979) also characterized the species by having very large colonies with thick and polysiphonic stems irregularly branched repeatedly in several planes. She also indicated that young colonies have a more ordered branching: primary branches alternately arranged, second-order ones in different planes. Millard (1977) described as Halecium dufresnae a new species that agrees in every detail with H. incertus and, in fact, Stepanjants (1979) already considered this species conspecific with H. incertus . Millard’s (1977) material also has thick fascicled stem (up to 245 mm high), branching and re-branching irregularly, but mainly in one plane. Although it has not been possible to re-describe the general appearance of the colony of H. macrocaulus from the material examined, according to Watson’s (2008) description it is clear that H. macrocaulus has robust, polysiphonic and much branched stems. In addition, although Watson (2008) indicated that forks arise from within a hydrotheca, in the material examined here I found only branches originating just below the cauline hydrothecae. Watson (2008: 173) also indicated the presence of a “septum (false diaphragm) of perisarc passing diagonally through hydrophore from near junction of diaphragm with abcauline wall to adcauline wall”. This “false diaphragm” clearly corresponds with a pseudodiaphragm as it has been unequivocally demonstrated by examining the holotype material of H. macrocaulus (cf. Fig. 6 F). Halecium macrocaulus is undistinguishable from H. incertus and it is considered here conspecific with Naumov & Stepanjants’ species. They agree in colony structure, with thick stems profusely and irregularly branched, shape and size of hydrotheca, presence of pseudodiaphragm, sessile hydrophores, and size of nematocysts. The single difference concerns the presence of acrocyst in H. incertus , not described for H. macrocaulus . However, this could be explained by the fact that the gonothecae described for H. macrocaulus are either male or female but immature. As it has been shown above, in H. incertus , it is possible to find in the same colony gonothecae with acrocyst, where an embryo is completing its development, together with others where an embryo is little developed and still within the gonotheca with the surrounding acrocyst. The shape of the gonotheca of H. macrocaulus [Fig. 6 I; see also Figure 9 B by Watson (2008: 174)] is identical to that I found in H. incertus from Bouvet (cf. Fig. 7 D, G). It seems clear, from the above-shown descriptions that H. incertus is characterised by having large (up to 300 mm high), thick, polysiphonic stems giving rise to also polysiphonic, lower-order branches in one or several planes. Consequently, I conclude that the material ascribed to H. incertus by Peña Cantero (2008, 2009, 2012) belongs to a different, described below, new species to science, Halecium pseudoincertus sp. nov. Ecology and distribution. Halecium incertus has been found at depths from 15 (Stepanjants 1979) to 693 m (Branch & Williams 1993), on rock (Stepanjants 1979; Branch & Williams 1993), and gravel and mud (Stepanjants 1979). Gonothecae in April (Millard 1977; Stepanjants 1979), November (Peña Cantero & Gili 2006), and from December to February (Stepanjants 1979). Halecium incertus seems to have an Antarctic –Kerguélen distribution (Peña Cantero & Gili 2006), having been found in both Antarctic and sub-Antarctic waters. In the latter, it is known from off Crozet (Millard 1977; Stepanjants 1979), Kerguélen (Stepanjants 1979) and the Marion and Prince Edward islands area (Branch & Williams 1993). In Antarctic waters, it is known from the Sodruzestva Sea (Naumov & Stepanjants 1962), off the Amery Ice Shelf (Stepanjants 1979), and off Mawson Coast (Watson 2008 as H. macrocaulus ), in East Antarctica, and off Bouvet (Peña Cantero & Gili 2006). : Published as part of Peña Cantero, Álvaro L., 2014, Revision of the Antarctic species of Halecium Oken, 1815 (Cnidaria, Hydrozoa, Haleciidae), pp. 243-280 in Zootaxa 3790 (2) on pages 256-261, DOI: 10.11646/zootaxa.3790.2.2, http://zenodo.org/record/226890 : {"references": ["Naumov, D. V. & Stepanjants, S. D. (1962) Hydroida (Thecaphora) collected by the Soviet Antarctic Expedition on the M / V Ob in antarctic and subantarctic waters. In: Biological results of the Soviet Antarctic Expedition, 1955 - 1958, 1. Issledovaniya Fauny Morei, 1 (9), 68 - 106.", "Stepanjants, S. D. (1979) Hydroids of the antarctic and subantarctic waters. In: Biological results of the Soviet Antarctic Expedition, 6. Issledovaniya Fauny Morei, 20 (30), 1 - 200, pls 1 - 25. [in Russian]", "Vervoort, W. & Watson, J. E. (2003) The Marine Fauna of New Zealand: Leptothecata (Cnidaria: Hydrozoa) (Thecate Hydroids). NIWA Biodiversity Memoir, 119, 1 - 538, figs. 1 - 108.", "Pena Cantero, A. L. (2004) How rich is the deep-sea Antarctic benthic hydroid fauna? Polar Biology, 27, 767 - 774. http: // dx. doi. org / 10.1007 / s 00300 - 004 - 0654 - 9", "Pena Cantero, A. L. & Gili, J. M. (2006) Benthic hydroids (Cnidaria, Hydrozoa) from off Bouvet Island (Antarctic Ocean). Polar Biology, 29, 764 - 771. http: // dx. doi. org / 10.1007 / s 00300 - 006 - 0113 - x", "Millard, N. A. H. (1977) Hydroids from the Kerguelen and Crozet shelves, collected by the cruise MD. 03 of the Marion-Dufresne. Annals of the South African Museum, 73 (1), 1 - 47.", "Branch, M. L. & Williams, G. C. (1993) The Hydrozoa, Octocorallia and Scleractinia of subantarctic Marion and Prince Edward Islands: illustrated keys to the species and results of the 1982 - 1989 University of Cape Town surveys. South African Journal of Antarctic Research, 23 (1 - 2), 3 - 24.", "Watson, J. E. (2008) Hydroids of the BANZARE expeditions, 1929 - 1931: the family Haleciidae (Hydrozoa, Leptothecata) from the Australian Antarctic Territory. Memoirs of the Museum of Victoria, 65, 165 - 178.", "Pena Cantero, A. L. (2008) Benthic hydroids (Cnidaria: Hydrozoa) from the Spanish Antarctic expedition Bentart 95. Polar Biology, 31, 451 - 464. http: // dx. doi. org / 10.1007 / s 00300 - 007 - 0371 - 2"]} Text Amery Ice Shelf Antarc* Antarctic Antarctic Ocean Antarctica Bouvet Island East Antarctica Enderby Land Ice Shelf Prince Edward Islands DataCite Metadata Store (German National Library of Science and Technology) Antarctic The Antarctic East Antarctica Kerguelen Australian Antarctic Territory New Zealand Antarctic Ocean Amery ENVELOPE(-94.063,-94.063,56.565,56.565) Amery Ice Shelf ENVELOPE(71.000,71.000,-69.750,-69.750) Bouvet ENVELOPE(3.358,3.358,-54.422,-54.422) Bouvet Island ENVELOPE(3.358,3.358,-54.422,-54.422) Pena ENVELOPE(40.562,40.562,63.490,63.490) Mawson Coast ENVELOPE(63.000,63.000,-68.000,-68.000) |