The type species of the genus Orbitolina D’Orbigny, 1850 (Foraminifera)

A number of species have been suggested as type species of the genus Orbitolina d’Orbigny, 1850, notably Madreporites lenticularis Blumenbach, 1805, Orbulites concava Lamarck, 1816 and Orbitolina gigantea d’Orbigny, 1850. It is shown that the correct type species is Orbitolina gigantea, although this is in fact a species of coral. Consequently in order to preserve the concept of Orbitolina as a foraminiferal genus, we herein recommend to the ICZN the proposal of Orbulites concava as a replacement type species. This would negate the need for a major revision of orbitolinid taxonomy and allows the genus Palorbitolina Schroeder, 1963 to remain valid.


INTRODUCTION
The typically Tethyan, Cretaceous larger foraminifera] genus Orbitolina was erected by d'Orbigny in 1850. Because of uncertainty in the original designation of a type species for this genus, a number of species have since been referred to as "type species". This has led to some confusion concerning the taxonomic concept of the genus and may have rendered other genera invalid because of problems with type species priority. In particular, the commonly used generic name Palorbitolina Schroeder, 1963 has been thought by some to be invalid, because the type species of that genus, Madreporites lenticularis Blumenbach, 1805, has been described, e.g. by Douglass, Loeblich and Tappan (1964), as the type species of Orbitolina. If this were the case it would have tremendous taxonomic implications. Not only would the name Palorbitolina be unavailable, but most species commonly regarded as belonging to Orbitolina would have to be assigned to a new genus. This is because Schroeder (1964a,b;1975) has shown that Palorbitolina is morphologically and phylogenetically distinct from Orbitolina. Therefore if the true nature of Orbitolina is that commonly regarded as Palorbitolina (i.e. that of the species lenticularis), then other species thought today to be Orbitolina (e.g. 0. concava (Lamarck, 1816) (Orbulites) or 0. texana (Roemer, 1849) (Orbitulites)) could not belong to that genus because of the observations of Schroeder (opp. cit. ) .
To clarify these problems a detailed examination of the original description of the genus Orbitolina and subsequent type species designations has been carried out.

Original designation
The first problem to address in this review is to establish if d'Orbigny designated a type species for Orbitolina in his original 1850 description.
Orbitolina is first mentioned on page 143 of volume 2 of the "Prodrome de Paleontologie stratigraphique universelle des animaux mollusques & rayonnes faisant suite au cours elementaire de Paleontologie et de Geologie stratigraphiques". There is no mention of Orbitolina in either volume 1 or 3 of this book.
It is important to note that volume is arranged in stratigraphic order. Hence the first species mentioned under Orbitolina is lenticulata in the section "Foraminiferes", within the chapter "19e etage -Albien". In total six species are listed under the genus Orbitolina in stratigraphic order. D'Orbigny does not indicate any particular species to be the type, and the stratigraphic nature of the volume implies that the first mentioned species under a genus is not necessarily the type.
It is clear, therefore, that no type species was designated for Orbitolina by d'Orbigny, and that lenticulata (=lenticularis) is not automatically the type species simply because it is listed first. This was first noted by Schroeder (1963) in a paper which established lenticularis as type species of the new subgenus (later genus) Palorbitolina.
As demonstrated above there is neither an original type species designation by d'orbigny, nor is the genus montypic in the reference containing the original description.

Subsequent designation
All six species recorded by d'Orbigny (1850) under Orbitolina have equal claim as type species. According to Article 69(a) of the International Code of Zoological Nomenclature (ICZN) (Ride et al., 1985), the first published designation of a type species subsequent to the original publication of the genus should be regarded as the only valid one.
There are, in fact, several subsequent quotations which could be regarded as designations of a type species for Orbitolina. (i) According to Parker and Jones (1860:35) "the conical, hemispherical and flattened forms of Orbitolinu so common in the Cretaceous deposits, and known under twelve or more different names, are referable to one specific type, namely the 0. concuva, Lamarck, sp. and to this type not only these large . . ." However, this quotation, nor any that follow it in the text, is not really valid as a type designation, as these authors were not using type in the sense of "type species of a genus", but rather as an indication of the "typical form of a species." Indeed on page 38 we read "we regard it (0. concava) as the type of a species including numerous varietys" . In their recent monograph of foraminfera genera, Loeblich and Tappan (1988:166) cited this reference by Parker and Jones (up. cit.), as a valid subsequent designation of a type species, and thus regarded Orbulites concava Lamarck, 1816, as the correct type species of Orbitolina. As noted above, we cannot agree with their opinion that the Parker and Jones reference is a valid subsequent designation, although for different reasons, as will be shown, we would recommend that 0. concava be regarded as type species.
The reference "Dollfus, 1905" of Ellis and Messina relates to a review by that author on a paper published by Prever (in Prever and Silvestri, 1905). In this review Dollfus (1905:232)  ." However, the second half of this statement made by Dollfus is wrong; Prever has never designated 0. lenticularis as type species of Orbitolina. On the contrary, 0. lenticularis belongs to the species which were eliminated by this latter author (1905:469; ""il lavoro di revisione compiuto, mi ha obbligato a distruggere parecchie delle specie gia istituite ed anche di quelle or nominate, ed in cambio a crearne delle nuove") .
(iv) Davies (1939:786) pointed out that "0. concava seems to be the form best indicated in the 'Prodrome' itself. It is also the best for studying the genus, being usually better preserved as well as much larger than 0. lenticularis. It should obviously, in my opinion, be taken as the type of Orbitolina." Davies (op. cit.) therefore selected 0. concava as type species. By dong so he hoped to alleviate the taxonomic problems caused by Cushman's designation of the coral 0. gigantea (= Cyclolites) as type species. In fact Cushman in the 1950 edition of his text, named 0. concava as the type species. A number of other workers have also agreed with Davies's opinion that 0. concava should be regarded as the type species of Orbitolina. These include Henson (1948) and Sahni and Sastri (1957).
(v) Thalmann (1950509) proposed Orbitolina texana (Roemer, 1849) (= Orbitulites texanus Roemer, 1849) as a substitute type species in place of Orbitolina concava. However, since this species is not among those originally included under the generic name by d'Orbigny , it can be immediately excluded from consideration as a type species (ICZN Article 69a). (vi) Douglass (1960a:28) and Douglass, Leoblich and Tappan (1964:C309) considered Orbitolina Zenticularis to be the type species of the genus. Douglass (op. cit.) is of the opinion that "only one species is referred to the genus in this, the original description. The genus as described is therefore monotypic, even though five other species are referred to it in later sections of the volume." As demonstrated above, the stratigraphic nature of the "Prodrome" implies that the first mentioned species under a genus is not necessarily the type. For this reason, the arguments of Douglass and Douglass et al. (op. cit.), which were also followed by Hofker (1963:220;1966b:9), are invalid (see also Schroeder, 1963:35 1).

CONCLUSIONS AND RECOMMENDATIONS
It is clear that despite the arguments of Douglass (1960a), Hofker (1963) and Douglass, Leoblich and Tappan (1964), no original designation of a type species of Orbitolina was made by d'Orbigny (1850), nor was the genus monotypic in the original description. Hence, Madreporites lenticularis (= Orbitolina lenticularis) is not automatically the type species.
The first designation of a type species is that of Cushman (1928), who nominated Orbitolina gigantea d'orbigny, 1850. According to Douville (1933) this taxon is a species of the coral genus Cyclolifes. In strict observance of the International Code of Zoological Nomenclature, Orbitolina d'orbigny, 1850 is a synonym of Cyclolites Lamarck, 1801 (see Wells, 1956 : F386).
If one accepts this situation, then the numerous species regarded as belonging to Orbitolina would have to be assigned to a new genus. Therefore we recommend the suppression of Orbitolina gigantea as type species and the recognition of Orbitolina concava as replacement type species of Orbitolina, as originally suggested by Davies (1939). This will negate the need for a major revision of orbitolinid taxonomy and allow the genus Palorbitolina to remain valid. In this context an official application has been made to the International Commission on Zoological Nomenclature to implement the above recommendations (Case 2663, Schroeder and Simmons, 1988).
It is worth noting that Orbitolina concava (= Orbulites concava Lamarck, 1816) is not the same taxon as Orbitolites concava Lamarck, 1801. As demonstrated by Parker and Jones (1860) and Schroeder (1962), the earlier named species (in fact a bryozoan) cannot be considered as the type of Orbitolina concava. Hence it is Orbitolina concava (Lamarck, 1816) that should be regarded as the valid type species of the genus Orbitolina.