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Relationships of Lophophyllid Corals
The American lophophyllid corals commonly have been referred to the genus Lophophyllum Edwards and Haine (1850). Studies on the genotype species of Lophophyllum, which is a Lower Carboniferous coral from Belguim, and work on column-bearing corals in many parts of the world have thrown considerable doubt on this generic assignment. The understanding and application of provisions of the International Rules of Zoological Nomenclature vary widely. Differences in characters among Late Paleozoic lophophyllid rugose corals, conjoined with variations in usage and interpretation of available data by different workers, have given rise to many inaccuracies and differences in taxonomy. Before beginning a description of the lophophyllid corals some discussion of taxonomic problems is needed.
Lophophyllum, Konickophyllum, and Lophophyllidium
The original description of Lophophyllum by Edwards and Haime (1850, p. lxvi) is as follows:
Corallum resembling Zaphrentis, excepting that a crestiform columella occupies the centre of the calice, and is in continuity by one of its ends with a small septum, placed in the middle of the septal fosula. and by the other end with the opposite primary septum.
The type species was given as "Lophophyllum Konincki, nob.," but this species was not described or illustrated until 1851, at which time the genus was further characterized (Edward and Haime, 1851, p. 349) as follows:
Polypier subconique, entouré d'une épithèque complète; columelle lamellaire et cristiforme occupant Ie centre du calice, et se continuant par une de ses extrémités avec une petite cloison située au milieu de la fossette septale, et par l'autre extrémité avec la cloison primaire opposée.
La présence d'une petite columelle cristiforme sépare bien ce genre de toutes les autres Zaphrentinae oè l'organe axillaire manque complétement. Nous connaissons trois espèces, deux appartiennent au terrain carbonifère et la troisième au devonien.
The type of this species, furnished by De Koninck, was from Lower Carboniferous strata at Tournai, Belgium.
Subsequent to the work of Edwards and Haime other students of the rugose corals obtained from this original description the concept that Lophophyllum was a genus established for a coral of zaphrentid type, having one of the protosepta prolonged and somewhat thickened. No further study of the true characters of the genotype species was published until 1911.
In 1876 Thomson and Nicholson (1876, p. 290) established the genus Koninckophyllum, with K. magnificum, n. sp., as genotype. This genus was described as a solitary or compound coral having septa that extend only part of the distance to the axial region, bearing a wide peripheral band of very minute dissepiments, an axial region containing close-set arched tabulae, and a small, compressed, compact or imperfectly cellular column that is shown by longitudinal sections to be either continuous or interrupted. Thomson and Nicholson state that Koninckophyllum differs from Lophophyllum in "the totally different form and connexions of the columella, and the less developed conditions of the septa, and, even more strikingly, by its extraordinarily minute and dense zone of vesicular tissue forming the periphery of the corallum."
Small conical rugose corals that bear a solid column but have relatively little vesicular structure, such as Fasciculophyllum eruca McCoy from Europe and Cyathaxoma prolifera McChesney from America, were subsequently referred to Lophophyllum. Corals having a thin laterally compressed, continuous or interrupted column and a wide dissepimental zone were referred to Koninckophyllum.
Carruthers (1913, p. 50) has pointed out that four years before publication of Edwards and Haime's monograph proposing the new genus Lophophyllum, based on L. konincki from Tournai, another species of rugose coral from Tournai was described by Michelin (1846, p. 258) as a new species. This was called Cyathaxonia tortuosa. The type specimens of both L. konincki and C. tortuosa are missing from the remnants of the collections of these authors at the Museum de Paris and seemingly are lost (Carruthers, 1913, p. 49). Both species are described as having a smooth epitheca and a prominent axial column. Carruthers (1911, p. 152; 1913, p. 50), in making a study of topotype material from Tournai, found that there are only two corals from this locality having a prominent column. One of these, Cyathaxonia cornu Michelin, is "relatively very small and has strong longitudinal ribbing on the epitheca" and according to Carruthers is obviously not the form described as C. tortuosa or L. konincki. The other coral species "agrees with the figures and descriptions" of both C. tortuosa and L. konincki. Carruthers therefore places the name Lophophyllum konincki Edwards and Haime in synonomy with Cyathaxonia tortuosa Michelin. The presence of dissepiments and the nature of the axial column in this species, however, does not permit its assignment to Cyathaxonia, and so the genus Lophophyllum is recognized as valid, with C. tortuosa Michelin as the genotype.
The revised generic diagnosis of Lophophyllum based on the study of the topotype material by Carruthers is as follows:
The corallites are solitary, turbinate, and enclosed by a theca; major septa meet at the center in early growth stages, one of them, generally the counter septum, is thickened at the inner end so as to form a moderately prominent axial column that projects upward into the calyx, but the column may be discontinuous; tabulae that arch upwards in the center to a varying degree occur below the floor of the calyx, and in the mature part of the corallite dissepiments appear between the tabulate area and the outer wall; unlike Dibunophyllum, there is no axial zone characterized by more numerous or vesicular tabulae or by a system of vertical lamellae distinct from the septa (Moore and Jeffords, 1941 p. 80).
Carruthers (1913, p. 53) concludes that
those corals referred by Thomson and Nicholson and other authors to Lophophyllum (e. g., L. proliferum and L. eruca) do not develop dissepiments at any stage of growth, and are essentially Zaphrentes [sic] having one of the septa thickened at the inner end. It may be convenient at some future time to group them as a sub-genus of Zaphrentis, but for the present such a course is not considered advisable.
Carruthers (1913, p. 52) indicated that some of the species included in Koninckophyllum have essentially the same characters as Lophophyllum tortuosum. The genus Koninckophyllum has been interpreted in several ways (Vaughan, 1905, p. 281; Sibly, 1908, p. 70; Gregory, 1917, p. 236; Lewis, 1935, p. 133), but its taxonomic position does not call for discussion here, except for consideration of its confusion with Lophophyllum.
Vaughan (1915, p. 39) asserted that Carruthers has not shown any stage of Cyathaxonia tortuosa that resembles Edwards and Haime's (1851, pl. 3, fig. 4, 4a) figure of Lophophyllum konincki and thus Carruthers merely assumes the two species to be identical. The specimen described by Carruthers, however, is taken to represent a new genus, which is named Eostrotion Vaughan (1915, p. 39). Hill (1939, p. 87) has pointed out that Vaughan was unduly influenced by theories of evolutionary trends in the phylogeny of Lithostrotion; and because the forms assigned to Eostrotion show seemingly continuous morphological variation from those referred to Koninckophyllum, she concluded that they do not constitute a distinct generic group.
If the conclusions of Carruthers are accepted and corals like those previously placed in Koninckophyllum are referred to Lophophyllum, several species already assigned to the latter genus must be removed. For these, however, no generic name was available when Carruthers published his discussion.
Girty (1915), in a study of lophophyllid corals from the Wewoka formation of Oklahoma, was uncertain as to the proper generic classification of Lophophyllum proliferum. He based his understanding of Lophophyllum on the original description of that genus and the illustrations of L. konincki by Edwards and Haime, and generic descriptions given by other writers. He was rather uncertain as to the differences between Lophophyllum and Cyathaxonia but concluded that L. profundum shows fewer departures from the characters of Lophophyllum. In another paper Girty (1915a, p. 319) says:
Insofar as I know the facts, Lophophyllum profundum is not in essential agreement with the genus Lophophyllum as based on Lophophyllum konincki which Milne-Edwards and Haime named as the genotype. It has opposite the septum [sic, error for fossula?] the fossula [sic, error for septum?] (the counter septum) connected with the pseudo-colummella, not the septum in the fossula (the cardinal septum) as in typical Lophophyllum, and the somewhat obscure radiating structure of the pseudo-colummella may not be found in Lophophyllum konincki. Furthermore, the fossula is situated on the convex side of the corallum in L. konincki and on the concave side in L. profundum.
Study of many of these lophophyllid corals indicates that the position of the fossula in relation to the curvature of the corallite is of little generic significance. Grabau (1922, p. 13) suggests that curvature in a plane other than that of the cardinal and counter septa is probably due to a pathologic cause. Many Upper Carboniferous and Lower Permian species of lophophyllid corals, however, are consistently curved in the alar plane.
Douglas (1920, p. 42), in describing some lophophyllid corals from South America that have a solid axial column and lack dissepiments, recognized that these could not be included in Lophophyllum as defined by Carruthers. No name was proposed by Douglas, and they were termed "Lophophylloid Zaphrentids" because they seemed essentially similar to Zaphrentis except for the column. Chi (1938, p. 161) has since referred these corals from Peru to Sinophyllum.
In 1928 Grabau described several types of simple column-bearing rugose corals and, for the group of forms that had been referred generally to Lophophyllum, he set up the new genus Lophophyllidium, with the American species Cyathaxonia prolifera McChesney as genotype. In the same paragraph in which this new genus is proposed Grabau (1928, p. 99) states:
It may, however, be remarked that since corals of the L. tortuosum type have been described as Koninckophyllum, though the majority of the species figured by Thomson and Nicholson show a more extensive peripheral zone of dissepiments, that it does not seem altogether advisable to apply the law of priority strictly in this case by removing the well-known species from the genus Lophophyllum and placing therein the species of Koninckophyllum, as suggested by Carruthers. My own opinion would be that less confusion would arise if Lophophyllum were to be retained for the species congeneric with L. proliferum McChesney or L. profundum E. and H. and more specialized Lower Carboniferous species retained in the genus Koninckophyllum.
Lophophyllidium has been used by most authors for small solitary horn corals lacking dissepiments but having tabulae and a prominent solid rodlike column that is formed by the axial thickening of the counter septum.
Huang has employed Koninckophyllum and Lophophyllum in the sense of their usage previous to studies by Carruthers. He concludes (Huang, 1932, p. 22):
It is to be remembered that corals congeneric with L. proliferum McChesney have for years been generally considered as Lophophyllum while those congeneric with L. tortuosum (Michelin) are customarily taken as Koninckophyllum. Such a wrong practice has been followed so long that it will cause great inconvenience and confusion if attempts are made to correct it. The creation of a new genus name is also not a good remedy since it will hardly be followed by other paleontologists. I am of the opinion therefore that Lophophyllum is to be applied for these species which are congeneric with L. proliferum while Koninckophyllum is to be retained for types like L. tortuosum. In accordance with this I have given the name Lophophyllum to the species described in the following, which are of the type of L. proliferum.
Yu (1933) recognized the new genus Lophophyllidium but seems to have misunderstood the statements of Grabau regarding it. He states that Grabau suggested inclusion of the more specialized Lower Carboniferous species in Koninckophyllum, and accordingly he writes "those forms congeneric with L. tortuosum (Mich.) are referred to the genus Lophophyllum." Yu's quoted statement seems to be in error, inasmuch as Grabau clearly held that corals of the L. tortuosum type should be referred to Koninckophyllum and those of the L. proliferum type to Lophophyllum. Although Lophophyllidium was proposed by Grabau, he seems not to have favored its adoption.
Lewis (1935) has described several Lower Carboniferous corals from Nova Scotia that he refers to Lophophyllum. The genotype is given as Lophophyllum konincki, but the generic diagnosis resembles that given by Carruthers based on L. tortuosum. The description of Koninckophyllum (used as a subgenus of Lophophyllum) as a form having a "dissepimental zone typically narrow, but sometimes broad, when the coral is indistinguishable from Koninckophyllum Thomson and Nicholson" indicates his concept of the closely related character of the two genera.
Another British student of the corals, Stanley Smith (1934, p. 129) concludes that although Carruthers is probably right in considering Lophophyllum konincki conspecific with Cyathaxonia tortuosa, "his conclusion still requires further confirmation." C. prolifera is considered congeneric with L. konincki. It is agreed however that if the two Tournaisian forms are identical, and if corals of the L. proliferum type which do not advance beyond the L. konincki stage cannot be retained in Lophophyllum, they must be placed in Lophophyllidium.
The relations of several of the genera of Late Paleozoic lophophyllid corals were reviewed by Heritsch in 1936. The corals similar to Lophophyllum proliferum (McChesney) are definitely separated by him from Lophophyllum and placed in Lophophyllidium. It is recognized that the diagnosis of Lophophyllum, as given by Carruthers, approaches Koninckophyllum Thomson and Nicholson very closely but the two genera are regarded as possibly separable on morphologic grounds. Heritsch (1936a, p. 108) seems to have been misled by Grabau's incorrect use of the term dissepiments in describing Lophophyllidium profundum (Edwards and Haime). Chi (1938), Sanford (1939), Fomitehev (1938, 1939), and Moore and Jeffords (1941) have also assigned corals similar to Cyathaxonia prolifera to Lophophyllidium.
Hill reports (1939, p. 86) that Smith examined material presumed to have been studied by Edwards and Haime and that he thought one specimen possibly the same as figured by Edwards and Haime. Externally this specimen shows a zaphrentid arrangement of the septa and a column, but it has no dissepiments.
Hill (1939, p. 86) agrees that the specimens referred by Carruthers to L. tortuosum undoubtedly have the structural characteristics of Koninckophyllum. The statement that only one species from Tournai corresponds to the description of L. konincki she thinks is not necessarily true and cannot be proved because it is based only on negative evidence. Koninckophyllum is recognized as a valid genus by Hill, and the characters of Lophophyllum are considered to be unknown until the presumed type is sectioned.
Lang, Smith, and Thomas (1940, p. 81) report that recent examination of material from Tournai supports the conclusions of Carruthers, but final decision can come only after re-examination of the types of L. konincki.
Summary--This review of studies on genera of lophophyllid corals indicates that there are three different opinions as to the status of Lophophyllum, Koninckophyllum, and Lophophyllidium. A few authors entirely disregard the International Rules in using the name Lophophyllum for corals like L. proliferum and the name Koninckophyllum for species congeneric with L. tortuosum (the designated type of Lophophyllum). A second group accept the interpretation of Carruthers, and they refer lophophyllid corals that lack dissepiments to Lophophyllidium. Still others maintain either that the type of Lophophyllum konincki is still available and should be studied, or that Carruthers was incorrect in assuming his specimens to be conspecific with L. konincki. Those who concur in the belief that the characters of Lophophyllum are still unknown tend to refer corals similar to Cyathaxonia prolifera to Lophophyllum, and they do not recognize Lophophyllidium. Whether Koninckophyllum is synonymous with Lophophyllum, as inferred by Carruthers, is not a concern of this study.
Examination of the original figures of L. konincki by Edwards and Haime (1851, pl. 3, fig. 4, 4a) support Vaughan's contention that the specimen illustrated by Carruthers does not especially resemble the types. Carruthers (1911, p. 152), however, states that study of topotype material shows the original type of L. konincki to be only an immature form of L. tortuosum. The appearance of the weathered calyx also may show differences from the transverse sections. Recognition of this topotype material is believed justifiable inasmuch as unquestioned type material is not available and the genus Lophophyllum is taken to be based upon the species Cyathaxonia tortuosa Michelin (Carruthers, 1913, p. 50). Corals similar to C. prolifera are then properly placed in the genus Lophophyllidium as proposed by Grabau.
Lophocarinophyllum
The genus Lophocarinophyllum Grabau (1922, p. 46) with the genotype Lophophyllum (Lophocarinophyllum) acanthiseptum Grabau (1922, p. 51), was established for Chinese species that resemble Lophophyllidium in many respects but that seem to have a distinct origin. The youthful stage of these forms is characterized by the development of carinae of the Lopholasma type. These appear in cross sections as septal spines. Grabau believes that sections of young specimens of the genotype species are practically identical, except for the projecting column, with sections of adult examples of Lopholasma carinatum Simpson (1900, p. 207). Inasmuch as these structures have not been observed in any American species of Lophophyllidium, it is quite likely, as Grabau suggests, that these Chinese forms represent a different line of descent. They have been derived from some Lopholasma type of coral, whereas the American forms probably are derived from a coral of the Stereolasma type.
Sinophyllum
The genus Sinophyllum was established by Grabau (1938, p. 99) in his second volume on the Chinese Rugosa, the genotype being Lophophyllum pendulum. Grabau (1922, p. 48). This new genus was stated to differ from Lophophyllidium in having a thick and pendulum-shaped axial column and an inner wall formed by the flexed ends of the major septa (not seen in sections of the mature portions of the corallite). The shape of the column does not seem to be especially diagnostic, for this is observed to vary widely in American species that are thought to represent Lophophyllidium. The inner wall, formed by bending of the axial ends of the septa, as described by Grabau for Sinophyllum, is not found in American species assigned to Lophophyllidium. An inner wall that is commonly present in these forms is produced merely by thickening of the axial portions of the septa, supplemented by the addition of steroplasm. The illustrations of the genotype species given by Grabau (1922, pl. 1, figs. 15a-b, 16a-b; 1928, pl. 4, figs. 1a-e, 2a-d, 3a-c) do not show clearly this bending of the septa and many of the transverse sections show an inner wall identical with that of many American species of Lophophyllidium.
According to Grabau, Sinophyllum has fewer dissepiment than Lophophyllidium. Neither the genotype of Lophophyllidium nor other species correctly referred to the genus, however, have any dissepiments. Study of figures that are said by Grabau to contain dissepiments and careful reading of his introductory discussion of rugose coral morphology and terminology shows that he considered dissepiments to be obliquely placed troughlike structures, the bottom sloping inwards and the concavity being towards the polyp. They were also described as appearing in transverse section as connecting plates between the septa. This definition of dissepiments is not generally accepted by other students of corals. These plates between the septa in Sinophyllum are simply parts of the arched tabulae intersected by the transverse section. The reference to dissepiments in Lophophyllidium and Sinophyllum, as given by Grabau and repeated by others (Heritsch, 1936, 1936a; Chi, 1938, p. 159) is deemed incorrect. Species that have dissepiments, such as Lophophyllum profundum (Heritsch, 1936a, p. 108) must be assigned to other genera.
Sinophyllum resembles Lophophyllidium in all major features except for the nature of the inner wall. It is questionable whether this feature is sufficiently well developed in the genotype of Sinophyllum and is of sufficient importance to merit generic separation.
Rylstonia and Other Genera
Hudson and Platt (1927, p. 40) state that some of the North American corals usually referred to Lophophyllum profundum have axial columns similar to those of Rylstonia Hudson and Platt (p. 39) and differ mainly in the strong longitudinal ribbing of the theca. The type of Rylstonia, which is R. benecompacta Hudson and Platt (p. 44), is a small conical-cylindrical form having a thick solid column, numerous tabulae, and several rows of dissepiments. The column of another variety from the same locality shows conspicuous radiating lamellae around its periphery. The dissepiments, and especially the nature of the axial column and tabulae, indicate that Rylstonia is more closely related to clisiophyllid corals than to Lophophyllidium.
Okulitch and Albritton (1937, p. 24) described the genus Malonophyllum, with the type species Malonophyllum texanum, n. sp., on the basis of silicified fragments of column-bearing corals from the Leonard series, Permian, from the Malone Hills, Texas. This genus is assumed to differ from Lophophyllidium in the entire absence of tabulae, but the nature of the septa and major features of the column are essentially similar in these two genera (Moore and Jeffords, 1941, p. 76).
A new genus, Lophamplexus (Moore and Jeffords, 1941, p. 90), the type species of which is Lophamplexus eliasi, n. sp., was established to include small solitary conical-cylindrical corals resembling "Amplexus" in nature stages but having an axial column that is attached to the counter septum in the youthful parts of the corallite. These corals can be separated from those included in Lophophyllidium by the disappearance of the column in the mature part of the corallite and by the thin complete tabulae that are present above the termination of the column.
A number of types of Upper Carboniferous lophophyllid corals have been placed in genera more or less closely related to Lophophyllidium. Many of these, such as Lophophyllum, Arachnolasma Grabau (1922, p. 59), Carruthersella Garwood (1912, p. 555), Koninckocarinia Dobrolyubova (1937, p. 51, 77), Lophophylloides Stuckenberg (1904, p. 92) (?=Lophophyllum), Neokoninckophyllum Fomitchev (in Gorsky and others, 1939, p. 58), and Yuanophyllum Yu (1933, p. 26) may be distinguished readily by the presence of dissepiments. In addition, they have a very different type of axial column.
Taxonomic Status of Lophophyllid Corals
The classification of the Rugosa is now in an extremely confused state. Some students recognize many families and others only a few. As yet, too little information as to phylogeny of the corals is available, and too many examples of homeomorphy among these fossils are described or suspected to permit reliable determination of relationships of many genera.
Grabau (1928, p. 97) placed Lophophyllidium with other column-bearing corals in a new family called Lophophyllidae. Lophophyllum, to which corals belonging to Lophophyllidium were formerly referred, has been assigned to the Zaphrentidae by Zittel (1900) and others and to the Streptelasmidae (Grabau, 1922; Yoh and Huang, 1932; and Huang, 1932). The solitary horn corals that have a solid rodlike axial column and lack dissepiments, like Lophophyllidium, "Sinophyllum," Malonophyllum, and Lophocarinophyllum, seem to constitute a closely related group. Their relationship to the more highly developed but stratigraphically older genera, such as Lophophyllum, Arachnolasma, Histophyllum, Thomson (1879), and Yuanophyllum is not accurately known.
Uncertainty and difficulty that is encountered in seeking to formulate a satisfactory family classification justify omission of family assignment of the lophophyllid corals at this time.
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Kansas Geological Survey, Geology
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