Campanularia sp.

Peña Cantero, Álvaro L., 2022, On a few benthic hydroids (Cnidaria, Hydrozoa) from the Kerguelen Islands (southern Indian Ocean), including the description of a new species, Zootaxa 5165 (2), pp. 274-286 : 281-282

Campanularia sp.

( Fig. 4A–D )

Campanularia tincta .— Vanhöffen, 1910: 297–298, fig. 17d, e (only material from Kerguelen).

Campanularia sp. — Millard, 1977: 18–20, fig. 5F.

Material examined. PROTEKER 3: Ile Suhn , several hydrothecae on algae, C. pusilla and tubulariid stem ( MNHN IK – 2012–10430 ).

Description. Stolonal hydrorhiza giving rise to erect, slightly sinuous, smooth pedicels up to 2200 µm long and provided with a single distal hydrotheca.

Hydrotheca elongated ( Fig. 4A ), bell-shaped, 930–940 µm high, resting on a basal spherule, 50 µm high and 80 µm wide, clearly thinner than pedicel and basal chamber ( Fig. 4D ); basal chamber 60 µm high. Apparently without diaphragm. Distinct inflexion point at distal part of basal chamber ( Fig. 4A, D ); hydrothecal diameter markedly increasing just above basal chamber, smoothly up to the middle and roughly constant afterwards, distinctly increasing again at base of cusps ( Fig. 4A, C ). Hydrothecal aperture perfectly circular, 370 µm in diameter; rim provided with 12 sharp cusps (height 60 µm, distance between cusps 80–90 µm) ( Fig. 4A, C ), very slightly directed inwards and separated by deep embayments. Hydrotheca with fine longitudinal streaks running downwards from the cusps ( Fig. 4A, C ). Frequently with hydrothecal renovations ( Fig. 4C ) (up to third-order hydrothecae observed). Microbasic mastigophores, banana-shaped, 18.1±1.0 x 4.0±0.1 µm (n= 10), range 16.5–19.5 x 4.0–4.3 µm.

Remarks. In the sample studied, there are also distinctly larger and wider hydrothecae ( Fig. 4B ). They are bellshaped, 1030–1100 µm high and 430 µm in diameter at the aperture, resting on a basal spherule, 70 µm high and 110 µm wide, clearly much thinner than the basal chamber and the pedicel; basal chamber 80 µm high. In general, these hydrothecae lack the distinctive inflexion point above the basal chamber found in the others, the diameter gradually increasing from the basal part of the basal chamber to the distal third of the hydrotheca. They also lack the characteristic enlargement at the base of the cusps. The hydrotheca is provided with 14 long, thin cusps (height 80 µm, distance between cusps 100 µm). The microbasic mastigophores, also banana-shaped, are slightly smaller 16.0±0.7 x 4.0±0.3 µm (n= 10), range 15–17 x 3.5–4 µm. It could not be determined whether both types of hydrothecae belong to the same species.

Present material appears to be conspecific with the material described as Campanularia sp. by Millard (1977) from the nearby Crozet Islands. In her material, the hydrotheca is also deep, 600–900 µm high, but slightly thinner (250–330 µm in diameter at the rim), with parallel sides and a basal spherule of smaller diameter than the pedicel. Millard reported eight to ten thin, bluntly rounded cusps, but did not mention any increase in hydrothecal diameter at the base of the cusps.

Allman (1876; 1879) described a new species, Campanularia cylindrica , from Kerguelen. The material was provided with gonothecae “cylindrical above, with a flat summit, tapering below towards the very short peduncle, which springs from the creeping stolon.” Allman stated that “in the absence of any fuller knowledge of its gonosome, this species … is only provisionally referred to the genus Campanularia ”. According to Vanhöffen (1910), Allman’s species has gonothecae similar to those of Clytia . The material studied here agrees with Allman’s in the elongated shape of the hydrotheca, as well as in the number of hydrothecal cusps, but the basal part of the hydrotheca is clearly different.

In conclusion, the present material with elongated hydrothecae is almost certainly conspecific with Millard’s material and could be conspecific with Allman’s species; the material with larger and wider hydrothecae is otherwise similar to that reported from Kerguelen, as C. tincta Hincks, 1861 , by Vanhöffen (1910: 297, fig. 17d–e). However, the absence of gonothecae here, as was also the case in Millard’s and Vanhöffen’s material, precludes the identification to species level.

Ecology and distribution. Campanularia sp. was collected at a depth of 14 m off Suhm Island, epibiotic on algae, C. pusilla and tubulariid stem.

Figures

FIGURE 4. Campanularia sp.: A–B, hydrothecae; C, hydrothecal distal part showing cusps; D, distal part of pedicel, basal spherule and hydrothecal basal part. Sertularella contorta Kirchenpauer, 1884: E–F, hydrothecae; G, hydrotheca and basal part of branch; H, hydrotheca showing polyp and location of basal ‘tentacles’ (close-up showing tentacles). Scale bar: 200 µm (A, B, E–H), 100 µm (C, D).