Ptychogastria asteroides Haeckel 1879
Description
Ptychogastria asteroides (Haeckel, 1879)
Fig. 4A–B
Pectanthis asteroides Haeckel, 1879: 267.
Pectanthis asteroides – Haeckel 1881a: 17, pls 7–8; 1881b: 20, pls 7, 8. — Browne 1903: 25, 26, 29. — Maas 1906a: 492. — Bigelow 1909: 311. — Vanhöffen 1912: 386. — Beyer 1959: 126–130.
Ptychogastria asteroides – Mayer, 1910: 374. — Thiel 1932b: 478. — Kramp 1947: 5; 1957: 46; 1959: 180, 205, 223, 226; 1961: 241; 1968: 174. — Picard 1955: 68. — Bouillon 1985: 202. — Boero & Bouillon 1993: 266. — Gili et al. 1998: 116, 126, 129, 131, 132; 1999: 232, Fgs 6–7; 2000: 1517, 1526. — Bouillon & Boero 2000: 68. — Bouillon et al. 2000: 92; 2004: 240, Fg. 152A–C; 2006: 112.
DescriptionUmbrella 1–2 mm high and 4–5 mm wide, dome-shaped in a contracted state, and comparatively Fattened when relaxed. Mesoglea relatively thin, giving rise to a small, blunt, apical projection. Exumbrella with 16 radiating ribs (8 perradial and 8 interradial) alternating with as many grooves, giving the margin a “lobed” appearance. Each umbrellar “lobe” bears a group of 12–16 solid tentacles arranged in a few, horizontally stacked rows; the three large, uppermost tentacles Fliform, borne on a conical projection enveloping their bases; projection crowded with irregular, refringent, likely mineral inclusions, as well as with stenoteles; additional tentacles of two types, Fliform and adhesive; surface of all Fliform tentacles covered with successive rings of spherical stenoteles of varied sizes; adhesive tentacles with a few, scattered stenoteles, ending distally in adhesive pads; a total of 200–260 tentacles per medusa. A free, pendant statocyst in middle of each umbrellar lobe, below the lowest row of tentacles; short, club-shaped, with single, spherical to elliptical statolith. Manubrium about half the length of the subumbrellar cavity; quadrangular proximally and eight-lobed towards middle; mouth with four simple lips crowded with mainly large stenoteles and granular, gland cells. Eight radial canals, bound to the wall of the manubrium through 8 shelf-like mesenteries, connect to the ring canal; centripetal canals absent. A continuous ring of nematocysts below the groups of tentacles. Velum thick and broad. Eight pairs of ovoid gonads on either side of the manubrial lobes; members of a pair separated through a mesentery. Cnidome: only stenoteles in two size classes reported to date. Color: perradial ribs of exumbrella purple-red, expanding distally into an ovoid spot of the same color; umbrella margin between the groups of tentacles yellowish; manubrium gold-yellow; tentacles translucent-yellow; adhesive disks red; gonads red.
RemarksThe tentacles of this medusa were described and illustrated by Haeckel (1881a, 1881b) as hollow, which made Kramp (1947) doubt about its afFnities with the genus Ptychogastria. Later, Picard (1955) found the species again and stated that all its tentacles were solid. Haeckel also noted that “all sixteen [exumbrellar] ribs are tipped with nematocysts”, but his statement was subsequently invalidated by Gili et al. (1999).
The shape of the manubrium, as well as the position of gonads in Haeckel’s (1881b) account, is highly contradictory. In the legend of his Fg. 1 (pl. 7), he stated: “In the middle [,] the golden-yellow base of the stomach with the surrounding corona of red genitalia shines through the umbrella” and, indeed, a pair of gonads is illustrated on either side of an eight-lobed manubrium. A similar condition is seen in his pl. 7 Fg. 3. In contrast, his Fg. 2, from the same plate, depicts a quadrangular manubrium and eight pairs of gonads originating from the proximal parts of the radial canals, thus apparently Ftting the rather imprecise diagnosis he gave of the species (p. 20): “Eight egg-shaped genitalia in the proximal half of the radial canal (sic!), encircling the basis of the stomach in the form of an eight-rayed star, and halved by long radial mesogonia”. However, Haeckel (1881b: 23) seems to clarify his observations by stating the following: “The eight genitalia […] surround the basis of the stomach like an eight-rayed star”. Although not making speciFc comments, a similar situation is seen in the more recent account by Gili et al. (1999: 324, Fg. 6), who Fgured the gonads around a rather lobed manubrium, the unambiguous shape of which is even more evident in their Fg. 7 (right drawing). It is worth noting that the manubrial lobes in this species are less developed than in P. polaris.
In addition, the position of the marginal “lobes” of the umbrella (and, consequently, of the groups of tentacles) seems to be erroneous in Haeckel’s account. Indeed, he placed two lobes (with their respective tentacle groups) in each octant (pl. 7 Fgs 1–3), while Gili et al. (1999, Fg. 7) illustrate 8 of them as perradial, and the remaining 8 as interradial.
EcologyOften recorded in both intermediate waters above submarine canyons and near the sea Foor close to the continental shelf. Owing to the most frequent occurrence of the specimens in traps placed in intermediate waters than in those close to the bottom, lead Gili et al. (1999) to suspect that P. asteroides is a medusa that shows longer swimming periods compared to its congener P. polaris (see below). The specimens obtained by Picard (1955) from 10 m depth over a Posidonia bed are suspected to have been brought there fortuitously after a heavy sea episode. The normal bathymetric range varies between 200 m (Haeckel 1881b) and 1150 m (Gili et al. 1999).
DistributionMany recent records are from the northern part of the Mediterranean basin (France and Spain) (Gili et al. 2000), but the species is known to extend its distribution westwards to the Strait of Gibraltar (Haeckel 1881b).
Notes
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Linked records
Additional details
Identifiers
Biodiversity
- Family
- Ptychogastriidae
- Genus
- Ptychogastria
- Kingdom
- Animalia
- Order
- Trachymedusae
- Phylum
- Cnidaria
- Scientific name authorship
- Haeckel
- Species
- asteroides
- Taxon rank
- species
- Taxonomic concept label
- Ptychogastria asteroides Haeckel, 1879 sec. Galea, Roder, Walcher, Warmuth, Kohlberg & Fischer, 2016
References
- Haeckel E. 1879. Das System der Medusen. Erster Theil einer Monographie der Medusen. Mit einem Atlas von vierzig Tafeln. Gustav Fisher, Jena. http: // dx. doi. org / 10.5962 / bhl. title. 46856
- Haeckel E. 1881 a. Monographie der Medusen. Zweiter Theil. Erste Halfte: Die Tiefsee-Medusen der Challenger-Reise. Zweite Halfte: Der Organismus der Medusen. Gustav Fischer, Jena. http: // dx. doi. org / 10.5962 / bhl. title. 46856
- Browne E. T. 1903. Report on some medusae from Norway and Spitzbergen. Bergens Museum Arbog 1903: 1 - 36.
- Maas O. 1906 a. Die arktischen Medusen (ausschlieβlich der Polypenmedusen). Fauna Arctica 4 (3): 479 - 526.
- Bigelow H. B. 1909. Coelenterates from Labrador and Newfoundland, collected by Mr. Owen Bryant from July to October, 1908. Proceedings of the United States National Museum 37 (1706): 301 - 320. http: // dx. doi. org / 10.5479 / si. 00963801.37 - 1706.301
- Vanhoffen E. 1912. Die craspedoten Medusen der deutschen Sudpolar-Expedition. Deutsche Sudpolar- Expedition 1901 - 1903, Zoologie 5 (3): 351 - 396.
- Beyer F. 1959. A new, bottom-living trachymedusa from the Oslofjord. Description of the species, and a general discussion of the life conditions and fauna of the fjord deeps. Nytt Magasin for Zoologi 6: 121 - 143.
- Mayer A. G. 1910. Medusae of the world. Vol. II. The hydromedusae. Carnegie Institution of Washington Publication 109: 231 - 498. http: // dx. doi. org / 10.5962 / bhl. title. 5996
- Thiel M. E. 1932 b. Die Hydromedusen-Fauna des Nordlichen Eismeeres in tiergeographischer Betrachtung. Archiv fur Naturgeschichte, n. ser. 1 (3): 435 - 514.
- Kramp P. L. 1947. Medusae. III. Trachylina and Scyphozoa. Danish Ingolf Expedition 5 D (14): 1 - 66.
- Picard J. 1955. Nouvelles recherches sur les hydromeduses des herbiers mediterraneens de posidonies. Recueil des Travaux de la Station Marine d'Endoume 15: 59 - 71.
- Boero F. & Bouillon J. 1993. Zoogeography and life cycle patterns of Mediterranean hydromedusae (Cnidaria). Biological Journal of the Linnean Society 48: 239 - 266. http: // dx. doi. org / 10.1006 / bijl. 1993.1017 Bouillon J. 1985. Essai de classiFcation des Hydropolypes-Hydromeduses (Hydrozoa-Cnidaria). Indo- Malayan Zoology 1: 29 - 243.
- Gili J. M., Bouillon J., Pages F., Palanques A., Puig P. & Heussner S. 1998. Origin and biogeography of the deep-water Mediterranean hydromedusae including the description of two new species collected in submarine canyons of Northwestern Mediterranean. Scientia Marina 62 (1 - 2): 113 - 134. http: // dx. doi. org / 10.3989 / scimar. 1998.62 n 1 - 2113
- Bouillon J. & Boero F. 2000. Phylogeny and classiFcation of Hydroidomedusae. Synopsis of the families and genera of the Hydroidomedusae of the world, with a list of the worldwide species. Thalassia Salentina 24: 47 - 296.
- Haeckel E. 1881 b. Report on the deep-sea medusae dredged by H. M. S. Challenger, during the years 1873 - 1876. Report on the ScientiFc Results of the Voyage of H. M. S. Challenger during the years 1873 - 76, Zoology 4 (2): 1 - 154. http: // dx. doi. org / 10.5962 / bhl. title. 6513
- Gili J. M., Bouillon J., Pages F., Palanques A. & Puig P. 1999. Submarine canyons as habitats of proliFc plankton: three new deep-sea Hydroidomedusae in the western Mediterranean. Zoological Journal of the Linnean Society 125: 313 - 329. http: // dx. doi. org / 10.1006 / zjls. 1997.0107
- Bouillon J., Pages F., Gili J. M., Palanques A., Puig P. & Heussner S. 2000. Deep-water Hydromedusae from the Lacaze-Duthiers submarine canyon (Banyuls, northwestern Mediterranean) and description of two new genera, Guillea and Parateclaia. Scientia Marina 64 (Suppl. 1): 87 - 95. http: // dx. doi. org / 10.3989 / scimar. 2000.64 s 187