Tulpa tulipifera ( Allman, 1888 )

Cantero, Álvaro Luis Peña, 2025, On the species of Tulpa Stechow, 1921 (Cnidaria, Hydrozoa) with the description of two new species from sub-Antarctic waters, Zootaxa 5633 (1), pp. 51-78 : 54-57

Tulpa tulipifera ( Allman, 1888)

( Figs. 2a–b , 3 )

Campanularia tulipifera Allman, 1888: 20 , pl. 10 fig. 1.

? Campanularia tulipifera — Jäderholm, 1905: 15; Nutting, 1915: 40–41, pl. 5 fig. 1.

Tulpa tulipifera — Stechow, 1921: 254; Peña Cantero, 2024a: 11–15, fig. 9A–C.

Not Tulpa tulipifera — Vervoort, 1972: 90, fig. 25e; El Beshbeeshy, 2011: 85–88, fig. 25 (= Tulpa revelata sp. nov.)

? Tulpa tulpifera [sic]— Stepanjants, 1979: 34, pl. 6 figs 1A–D, pl. 25 fig. 3.

Tulpa diverticulata — Watson, 2003: 173–174, fig. 24A–D.

Material examined. TAN 0803 Stn 98, several hydrothecae and stems up to 20 mm high, with incomplete gonothecae ( NIWA 131357).

Description. Colonies consisting of stolons growing on substrate and giving rise to either long pedicels with a single distal hydrotheca ( Fig. 2a ) or erect, monosiphonic, unbranched stems up to 20 mm high. Stems with up to six hydrothecae on short pedicels, arranged alternately in almost unilateral pattern; sometimes distal hydrotheca present. Some pedicels with regenerative nodes.

Hydrotheca tulip-shaped, basal fourth strongly widening from annular thickening, then constant or decreasing distally and widening distinctly at aperture ( Fig. 2a ), giving it a trumpet-shaped appearance ( Fig. 3a–b ). Hydrothecal rim uneven, with 12 little-marked cusps, strongly everted ( Fig. 2b , 3a–b ), and sinuous (slightly outside, markedly inside). Sinuosity creating an alternate sequence of crests and troughs inside and outside hydrotheca ( Fig. 3c ). Inner crests more pronounced and acute, extending downward for a great extent. Rim external troughs corresponding to cusps, external crests to embayments. Outside hydrothecal wall with longitudinal, concave facets ( Fig. 2a ), corresponding to external troughs, laterally delimited by well-marked ridges extending downwards to basal fourth. Opposite pattern on inner hydrothecal wall. Prominent internal ridges ( Fig. 3c–g ), corresponding to external troughs, frequently with strong perisarc keel ( Fig. 3e ) running downwards along most distal part of hydrothecal wall. Rim frequently with one to three renovations ( Fig. 2a ), much more everted than primeval one. Hydrothecal perisarc generally with very fine transverse striations.

Gonothecae on stolons and stems, incomplete, conical (see Fig. 9C in Peña Cantero 2024a).

Remarks. The stolons creeping on the substrate may give rise to long free stolons, which may either bear a single distal hydrotheca or form additional hydrothecae with an alternate, almost unilateral arrangement. These can therefore be considered as stems. The diameter of the hydrothecal pedicel is smaller than that of the stolons; even the distalmost part of the erect stolons, some of which develop into stems, has a thinner portion before the distal hydrotheca.

The pedicels of the stolonal hydrothecae are significantly longer (up to 2840 µm) than those of the stem hydrothecae (1200–1600 µm).

In this species, the entire rim (i.e. cusps and embayments) is strongly everted, sometimes even directed downwards ( Fig. 3a–b ).

From Allman’s description and figures, it is evident that the hydrotheca has a wider basal part; as he described it, ‘hydrothecae … slightly narrowed behind the orifice, and again widening towards the base’. Although Allman stated that there are eight cusps, his figures show between 10 and 12. Longitudinal crests are also present on the inner side of the hydrotheca, and the pedicels are short, often with a node.

Peña Cantero (2024a) identified the present material as T. tulipifera based on the presence of stems, the absence of diverticula, and the shape and size of the hydrothecae. Here, I retain it under Allman’s species based on the absence of diverticula, the general shape of the hydrotheca, its strongly everted rim with little-marked cusps, and the presence of distinct ridges on the inner hydrothecal wall. The size of the hydrotheca is also consistent with Allman’s material (3810 µm in height and 1270 µm in diameter at the bulbous part).

Jäderholm (1905) attributed material from Burdwood Bank to this species, but provided no illustrations or description other than noting that the colonies were 10–12 cm high. It is therefore not possible to clarify its taxonomic position. However, Jäderholm apparently sent a fragment of this material to Nutting (cf. Nutting 1915), who pointed out that the hydrothecae were very large (3500 µm in height and 1000 µm in diameter), tubular, and with an everted rim with about 14 cusps corresponding ‘to a series of longitudinal flutings of the hydrothecal wall which extends downward almost to the base’ ( Nutting 1915: 41). This author also noted that the pedicels were very short (not more than one-fourth of the hydrothecal length) and smooth, except for a constriction at each end. Although Nutting indicated that the rim is gracefully everted, the hydrotheca he illustrated ( Nutting 1915: pl. 5 fig. 1) does not show this feature, at least not to the same extent as seen in T. tulipifera . Therefore, there is some uncertainty as to whether the Burdwood Bank material actually belongs to Allman’s species.

In my opinion, the material assigned to T. tulipifera by Vervoort (1972) does not belong to Allman’s species. The shape of the hydrotheca is clearly different, as the aperture is not markedly everted and the rim has 14 to 16 prominent cusps. Vervoort (1972) stated that ‘the hydrothecal margin is undulated, with the incisions between the teeth curving outwards and the rounded teeth curving inwards.’ In contrast, in T. tulipifera , the entire rim (i.e. both the cusps and embayments) is strongly everted, sometimes even downwards. El Beshbeeshy’s (2011) material is clearly conspecific with Vervoort’s and is, therefore, not considered to belong to T. tulipifera . The hydrothecal rim in El Beshbeeshy’s material is also sinuous, with 13 to 17 well-marked rounded cusps, and the longitudinal lines extend downward for about one-third of the hydrothecal length.

Stepanjants (1979) identified material from widely separated locations (i.e. Crozet, Kerguelen and the Patagonian shelf area) as T. tulipifera . From her description and figures, it seems plausible that she was indeed studying T. tulipifera material.According to her description, the hydrothecal rim is bent outwards, there are distinct longitudinal ribs, and deep grooves between them, extending downwards along the entire length of the hydrotheca, and, under high magnification, the perisarc of the hydrotheca is finely striate. These features, together with the shape of the hydrotheca shown in pl. 6 fig. 1B, strongly suggest that at least part of her material belongs to T. tulipifera .

Ecology and distribution. Tulpa tulipifera has been recorded from depths between 273 m ( Allman 1888) and 1064 m ( Watson 2003, as T. diverticulata ).

Tulpa tulipifera seems to be a sub-Antarctic species. It was originally described by Allman (1888) off Heard Island. More recent records also are from similar latitudes, north and south of Macquarie Island ( Watson 2003; Peña Cantero 2024a). There are unconfirmed records from Crozet, Kerguelen and the Patagonian shelf area ( Stepanjants 1979).

Figures

FIGURE 2. (a–b) Tulpa tulipifera Allman, 1888 (NIWA 131357): a) stolonal hydrotheca with pedicel; b) hydrothecal aperture. (c–d) Tulpa diverticulata Totton, 1930 (NIWA 130060): c) hydrotheca and distal part of pedicel; d) hydrothecal aperture with diverticula. Scale bar: 250 µm (b, d), 500 µm (a, c).

FIGURE 3. (a–h) Tulpa tulipifera Allman, 1888 (NIWA 131357): (a–b) distal part of hydrotheca showing strongly everted rim; c) hydrothecal aperture (upper view) showing rim sinuosity (more marked on the inner side); (d–g) details of the rim of the hydrothecal aperture (in e arrow pointing at perisarc keel); h) isorhiza. Scale bar: 200 µm (a–c), 100 µm (d–g), 10 µm (h).

FIGURE 9. (a–d) Larger nematocysts (isorhizas) of four species of Tulpa Stechow, 1921: a) T. diverticulata (NIWA 130060); b) Tulpa peculiaris sp. nov. (MNCN 2.03/690); c) Tulpa revelata sp. nov. (MNCN 2.03/692); d) T. tulipifera (NIWA 131357). Scale bar: 10 µm (a–d).