Cystonectae Polygastricae.

Pugh, P. R., 2019, A history of the sub-order Cystonectae (Hydrozoa: Siphonophorae), Zootaxa 4669 (1), pp. 1-91 : 52-54

Cystonectae Polygastricae. Family Physalidae .

And so we come to Haeckel’s (1888b) final cystonect family, the Physalidae . Haeckel begins by reviewing the history of the family and noted (ibid. p. 338) that: “All recent authors have accepted the genus Physalia as the only type of this family”. Ones hopes are raised that Haeckel will do the same! But those hopes are quickly dashed. First of all he re-established Brandt’s (1835) genera Salacia for species with a dorsal crest, and Alophota for those without one. He said (ibid. p. 339): “The family Physalidae was established in 1835 by Brandt ... He first distinguished two different subgenera in the genus Physalia , viz., (1) Salacia (or Physalia proper), with a chambered dorsal crest of the float; and (2) Alophota , without crest. This distinction, although not accepted by later authors, is very important, since the crestless state of the pneumatophore, regarded from a phylogenetic point of view, must necessarily precede the crested state”. Of course, it also applies from a developmental point of view. However, as noted above, Haeckel had already used the generic name Salacia as the basis of a completely different cystonect family. Haeckel (ibid.) continued: “We establish for these [the so-called species without a crest] the subfamily Alophotidae , and oppose it to the crest-bearing subfamily Caravellidae ”. In each sub-family Haeckel then uses the presence of only a single large tentacle or of many such tentacles to divide each into two genera.

Haeckel (1888b, p. 339) succinctly summarised the problems arising from many of the previous descriptions, but then made the situations even worse. He said: “The distinction of species in these four genera of Physalidae is a very difficult task, since the entire family is transformistic, and all the so-called “good species” are connected by Darwinian intermediate forms. Nevertheless, there exist a number of “geographical species” as local forms in the different seas. In the majority of the numerous descriptions the species of Physalidae are founded upon slight differences in the variable coloration, or different states of contraction of the very variable pneumatophore and other parts ... A better and more natural distinction of “relatively good species” will be got when the future observers carefully regard the following anatomical structures:— (1) the grouping and composition of the monogastric or polygastric cormidia; (2) the relation of the basal protosiphon (at the distal end of the float) to the secondary siphons (or metasiphons) on its ventral face; (3) the difference in structure and form of the pneumatophore, mainly at its apical and basal poles; (4) the structure of the crest, the number of its chambers, &c”.

Having established the sub-family Alophotidae for the physaliids without a crest, eight pages later Haeckel very confusingly changed the name of the sub-family to the Arethusidae, and included in it the genus Alophota with a new genus Arethusa . The genus Alophota , defined as being without a crest and with a single large main tentacle, was originally established by Brandt (1835) as a sub-genus of the genus Physalia . However, the Latin diagnosis of Physalia (Alophota) Olfersii (ibid. p. 238) stated “Tentacula 2”. Typically, Haeckel (1888b) did not mention, in the section on Alophota Brandt’s subspecies by name, although he did include it in his final list of siphonophore species. He decided that he had two other related species, A. giltschiana and A. mertensii , the description of the latter being left for his fabled Morphology of the Siphonophorae .

There is little point into going into any detail of Haeckel’s (1888b) descriptions of Alophota giltschiana or Arethusa challengeri (see Figure 25 ), the only two physaliids he illustrated. One could note that the maximum size of the float of the former “species” was 2 cm, with four “developed cormidia” in the main group; while for A. challeng- eri the float measured up to 5 cm and the number of tentacles, which unsurprisingly were larger than for the former species, was six to eight. This is only interesting because of its inexactitude as Totton (1960), and others before him, clearly established was that the maximum number of groups in each zone was seven. To put this into context let us remember that the pneumatophore of Physalia physalis can reach at least 30 cm in length, so Haeckel’s specimens were mere babies. As there is no value in continuing to discuss Haeckel’s misguided ideas on the family Physaliidae , it is simplest to list in full the species he included in the family ( Haeckel, 1888b, p. 372); all of which, apart from the nomina nuda, are considered by the present author to be junior synonyms of Physalia physalis :

Family PHYSALIDAE Brandt, 1835

Sub-family ARETHUSIDAE Haeckel, 1888b (Pneumatophore simple, without dorsal crest).

Genus Alophota Brandt, 1835 – A single large main tentacle.

Alophota olfersii Brandt, 1835

Alophota giltschiana Haeckel, 1888b

Alophota mertensii Haeckel, 1888b Nomen nudum

Genus Arethusa Haeckel, 1888b 51 – Several large main tentacles.

51 Haeckel (1888a) attributes the generic name Arethusa to Browne, but no date was given. However, Haeckel (1888b, p. 349) attributes the name to himself as “The genus Arethusa was established a century ago (in 1789) by Patrick Browne, for that gigantic Physalid of the Tropical Atlantic, which is known to the sailors as the “Portuguese Manof-War,” and which O. F. Müller and Gmelin had called Medusa caravella ... Since the generic name Arethusa was afterwards given up and replaced by Lamarck’s name Physalia , we employ here the former for the designation of those Physalidae which agree with Caravella in the possession of numerous large main tentacles, but differ from it in the absence of a polythalamous crest on the pneumatophore”. Nonetheless, the species that Haeckel (1888b) includes in this genus are very different from those that Haeckel (1888a) included.

Arethusa challengeri Haeckel, 1888b

Arethusa thalia Haeckel, 1888b Nomen nudum

Sub-family CARAVELLIDAE Haeckel, 1888b (Pneumatophore with dorsal crest).

Genus Physalia Lamarck, 1801 – Single large main tentacle

Physalia pelagica Bosc , 180252

Physalia cornuta Tilesius , 181353

Physalia utriculus Eschscholtz , 182954

Physalia megalista Lamarck , 181655

Genus Caravella Haeckel, 1888b – Several large main tentacles.

Caravella gigantea Haeckel, 1888b = Physalia cystisoma Lesson partim

= Physalia gigantea Bory de St. Vincent, 1804 Caravella maxima Haeckel, 1888b = Physalia caravella Eschscholtz , 182956

= Physalia arethusa Olfers, 1831

Figures

FIGURE 25. Left. Alophota giltschiana Haeckel, 1888b – corm diameter 1.5–2 cm; and Right. Arethusa challengeri Haeckel, 1888b – corm length 4–5 cm. Figures 3 and 4, respectively, from Haeckel (1888b) Plate XXVI.