Boros István (szerk.): A Magyar Természettudományi Múzeum évkönyve 5. (Budapest 1954)

Kolosváry, G.: On the known fossil Hydrozoa of Hungary

On the Known Fossil Hydrozoa of Hungary By G. К о 1 о s V á г у, Budapest ^ In Hungarian literature, E. К u t a s s y was the first to publish a paper on Hungarian fossil Hydrozoa. Of these animals, much neglected in Hungary, S t e i n m a n n has stated already in 1903 that fossils are very scanty between the Palaeozoic and the Tertiary-Recent forms. Though, with regard to distribution, the Mesozoic data are rather numerous, the number of species spreading to Middle Europe from the Mesozoic seas of Southern Europe and India are low. These also did not remain here long. Such were, for instance, Ну dract i n i a and H e t e r a s t r i d i a. At the end of the Jurassic, Ellipsactinia spread to Southern Europe and the Alpine regions, nor did this genus became completely native here. The westernmost point of its distribution : Stramberg (titon). It still lives in the Creataceous in the Mediterranean region. In the English and southern French cenoman, Parkeria appears, and dies out as swiftly. The »most ancient representative* of Hydractinia in the French cenoman is highly dubious and rare, though Thalamospongia, belonging to this family,can be found in the Neocom. We catch up with Hydractinia in the Eocene of Egypt, spreading in the Neogene from Italy to Crag Rag in England. — Palaeozoic Stromatoporoidea do not all become extinct at the end of the Palaeozic. This ancient group lives generally from the Silurian to the Eocone : its last four species perish in the Cretaceous. — According to S t e i n m a n n, Milleporidae are not only related to the old Stromatoporida, but are their descendants. Vinassa de Regny believes to find in Millestroma the connecting link between real Milleporidae and stromatoporid Hermatostroma. Gregory, namely, described a Hydrozoa, named »Millestroma«, from the Turon of Egypt, which he already took to be a connecting link. Steinmann, however, rightly doubted this, as it lacks gastrozoids, having only dactylozoids. — In 1935, Yabe and S u g i y a m a took the former Stromatoporida into the new family Milleporidiidae, relegating them thereby to the order Hydroidea.

— Mesozoic »Milleporids« are therefore Milleporidiids. True Milleporae are known only from the Tertiary stages. Vinassa de Regny considers genus Balatonia similar to the Millepora type, and so as the first, ancient, Triassic representative. He even mentions that Milleporidium is rather more related to Stromatoporidae than Balatonia, which should be an ancient form on the way of development towards Millepora. As, however, it becomes soon extinct, I take it rather as a side-branch ; anyhow, it cannot be connected directly back to Stromatoporoidea. — Steinmann has some doubts with regard to the Triassic Sfromactinia of the Mts. Bakony, described by Vinassa de Regny, too. Vinassa mentions that Stromactinia is really an Ellipsactinia without zoid tubes. Nor did the absence of zoid tubes prove to be a separating character in the case of the genus Stoliczkaria, since it was shown in the case of Hydractinia michelini, too, that the lacking of the zoid tubes may be the result of simple populative variations. According to К tit assy, Stoliczkaria does have zoid tubes, but, owing to frequently becoming filled up during fossilization, they tend to be invisible. 4)n this ground, К u t a s s y considers Stoliczkaria a Heterastridium, and draws the necessary synonimy. The structure of Spheractinoidea and Stromatoporoidea is striated.This dominating striated structure is an ancient type. In the structure of Millepridiida striated development is also considerable yet, though we cannot find it any more in the tip of the young branches of some colonies. The structure of Balatonia is rather radial (its striated structure is more modest). It follows that direct descent of Hydroidea from Stromatoporoidea can manifestly not be shown. This could have been the case only in the most ancient times, at the beginning of the Palacozoicum.out of which we have no witnessing fossils! Dawson denied the direct connection pi origin between Hydractinia and Stromatoporida types. If we compare