Geological Survey Professional Paper 58 The Guadalupian Fauna

ECHINODERMATA.

Echinoderms are usually rare at the later horizons of the Paleozoic, and in the Guadalupian fauna they form but an insignificant factor. Crinoids are represented only by fragments of stems, which occur in many of the collections, though never in abundance. Of the cystoids our material has furnished a single form of considerable interest, representing both a genus and a species which are new. Echinoids occurring as dissociated plates and fragments of radioles are rare and of small size. Six varieties apparently can be discriminated, but the material is so imperfect that nothing has been described as new in this group.

Although the echinoderm remains of the Guadalupian are so scanty, it will be of interest to see how this class is represented in other faunas and wherever possible to make comparisons. The true crinoids, of which our collections furnish only stem fragments, are rather unusually well represented in the Salt Range fauna, where Waagen described 4 species of Cyathocrinus, 1 of Hydriocrinus, 2 of Poteriocrinus, and 1 of Philocrinus. No cystoids were found and only one species of echinoid, occurring as loose spines and plates. This was placed by Waagen in the genus Eocidaris and is not closely related to the corresponding Guadalupian types. The crinoid stems which Diener cites from Malla Sangcha and from Chitichun No. 1 may well be omitted from consideration, and the fact be pointed out—so far as it has significance when based on such imperfect data—that the Guadalupian fauna differs widely from those of the Salt Range and Himalaya with respect to this class of organisms.

In China remains of the Echinodermata are rare, the only record I have found being by Loczy, who notes fragments of stems and an occasional plate belonging to the Crinoidea.

Almost the same may be said of the Carboniferous of the Indian Archipelago. Roemer cites some crinoid stems from Sumatra and Martin does the same for Timor. From Timor, Beyrich not only obtained the usual crinoid stems, but described a new genus and species of cystoid (Hypocrinus) of considerable interest in this connection, since it appears to be related to the Guadalupian Cœnocystis. In his treatment of the faunas of Timor and Rotti Rothpletz discusses at some length the fragments of crinoid stems, which his collection seems to have contained in considerable abundance. He likewise obtained a fragment of a radiole of an echinoid and an additional species of Hypocrinus.

In the Russian section the Moskovian contains a rather abundant echinoderm fauna. We have first, according to Trautschold, the echinoids Archæocidaris rossica, represented by a variety of parts, and Lepidesthes lævis; among the starfish, so rarely found in the Paleozoic, Palæaster montanus, Calliaster mirus, and Stenaster confluens. The crinoids are cited as Poteriocrinus originarius, P. multiplex, P. bijugus, Hydriocrinus pusillus, Cromyocrinus simplex, C. geminatus, C. ornatus, Phialocrinus patens, P. urna, Stemmatocrinus cernuus, Forbesiocrinus incurvus, and Platycrinus sp. This unusually extensive and varied fauna is entirely dissimilar to the much more meager representation of the Guadalupian.

Much less common appears to be the occurrence of this group at higher horizons. From the Gschelian Sibirzew lists radioles and plates of Archæocidaris (like A. rossica Von Buch) and fragments of Poteriocrinus and Cyathocrinus. Stuckenberg notes about the same assemblage, Cyathocrinus sp., Poteriocrinus sp., Archæocidaris sp., and Palæechinus paradoxus.

From the Artinskian Stuckenberg cites Palæechinus sp., Archæocidaris sp., and Cyathocrinus sp. The two echinoids resemble Archæocidaris cratis and Archæocidaris sp. a of the present report. The Kungurstufe furnished this author only Cyathocrinus sp. Sibirzew lists from the Artinsk Archæocidaris and Cyathocrinus.

From the Russian Permian Tschernyschew cites Cyathocrinus ramosus, Sibirzew the same, Netschajew Cyathocrinus cf. ramosus and Poteriocrinus quenstedti, and Golowkinsky Poteriocrinus quenstedti. In some of these, at all events, though not in the last, the identification is based on fragments of stems.

So far as comparisons can be made on this scanty evidence, the Guadalupian echinoderms do not resemble the Russian species to any extent. The absence from the fauna of determinable crinoids is worthy of some notice, though where there are stems there must of course have been cups. The presence of the cystid is also noteworthy.

In the fauna from Djoulfa Abich cites only Poteriocrinus, represented by stem fragments, and Arthaber recognized Cyathocrinus cf. ramosus, Cyathocrinus cf. virgalensis, and Poteriocrinus? sp. in reviewing Abich's fauna, the identifications in every case being based on stems alone. Only stems were found by Enderle also among his fossils from Balia Maaden.

Of data bearing on the representation of these types in the interesting fauna from Palermo, described by Gemmellaro, and in the related one from the Caruic Alps which Gortani and Schellwien have partially described I have found no trace; but in the German Dyas the echinoderms are again noted. Geinitz cites Eocidaris keyserlingi, Asterias bituminosa, and Cyathocrinus ramosus. To the two latter the Guadalupian fauna presents nothing comparable. Archæocidaris cratis and Archæocidaris sp. a resemble the radioles of Geinitz's Eocidaris keyserlingi, but apparently the two species belong to different genera.

From the English Permian, King cites Cyathocrinus ramosus and Archæocidaris verneuiliana (Palæechinus in the description of plates). The echinoid is of the same general type as Archæocidaris cratis and Archæocidaris sp. a, but we have as yet nothing which can be compared with the crinoid.

Toula's papers on the Carboniferous faunas of Spitzbergen contain references to crinoid stems alone, while from Nova Zembla he noted only an indeterminable species of Archæocidaris and Cyathocrinus sp., together with stem fragments. From two areas in the West Sahara, Stache obtained abundant crinoid stems, which he studied in great detail. Only fragmentary remains of the same group are recorded from South America. Gabb notes them from Peru, and Salter and Toula from Bolivia.

In De Koninck's account of the Carboniferous fossils of New South Wales a number of echinoderm species were noted belonging to the genera Synbathocrinus, Poteriocrinus, Actinocrinus, Platycrinus, Tribrachyocrinus, Cyathocrinus, and Palæaster. All appear to have come from the lower beds except the Tribrachyocrinus, the Cyathocrinus, and the Palæaster. Nothing at all resembling these species is known from the Guadalupian.

In the "Permo-Carboniferous" of Queensland and New Guinea echinoderms are unusually abundant—much better represented, at all events, than in the Guadalupian. Etheridge cites Actinocrinus (1 species), Platycrinus (1 species), Poteriocrinus (2 species), besides fragments of other forms; also, among the blastoids, Mesoblastus? (1 species), Granatocrinus? (1 species), and Tricœlocrinus? (1 species), while the echinoids are represented only by a single plate of Archæocidaris. There seems to be here scarcely any common ground with the Guadalupian.

Relating to the present discussion, I find listed in Weller's bibliography of North American Carboniferous invertebrates, species representing the crinoids and echinoids alone, the cystoids, blastoids, and asteroids being at present unknown. All species of lower Carboniferous (Mississippian) age have of course been eliminated from this list, and all such as have a purely western distribution.

Crinoids, while as a rule rare in the Pennsylvanian, in the aggregate constitute an extensive fauna, comprising 14 genera and 47 species, as follows:

The echinoids, while more plentiful, are much less varied. The only genera known are Archæocidaris and Eocidaris, the former with seven and the latter with one species. Since the publication of Weller's bulletin, from which the foregoing data were derived, a few additional species of echinoids and crinoids have been described, but they do not modify to any extent the previously known fauna.

One might easily be led too far in comparing the Guadalupian and Pennsylvanian faunas in point of their echinoderm representation, but so far as known the Guadalupian is without determinable crinoids, while cystoids, which, of a single type, are fairly abundant at one station in the Guadalupian, are unknown in the Pennsylvanian. As for the echinoids, a group which is represented in both faunas, it seems to be true that those of the Guadalupian are rarer and of smaller size than the Pennsylvanian representatives.

CYSTOIDEA.

Family CRYPTOCRINIDÆ Zittel.

Genus CŒNOCYSTIS n. gen.

The generic description of Cœnocystis is included in the description of the specific characters of Cœnocystis richardsoni, which is taken as the genotype.

CŒNOCYSTIS RICHARDSONI n. sp.

Pl. XXVII, figs. 19 to 22.

The lower half of the cup in this interesting species is composed of a calyx-like group of consolidated plates, representing apparently two serial rows. What may be regarded as the basal plates consists of an elongated cone, which is nearly solid or only partly calibrated, apparently formed by the consolidation of several plates whose line of juncture is now entirely lost. This conical basal portion is followed by a hemispherical expansion formed by five pentagonal primary plates of equal size. They are firmly joined with one another laterally, though the suture is distinctly marked by a depressed line. With the basal portion, however, they are so closely ankylosed that they appear for the most part to be continuous. Although there seems to be an obscure basal outline to this second series of plates, I suspect that this is rather a phenomenon than a reality. The contiguous upper angles of two adjacent plates of this series are deeply excavated for the relatively large anal pore. Similar pores appear to be symmetrically developed on the four remaining lines of suture, but these are much smaller. They have not been observed on the outside, but regularly appear as channels transversely cutting the thick basal cup. (See fig. 20 of Pl. XXVII.)

There may be some question whether the solid basal portion of this structure consists of two series of plates, according to the above interpretation, or of but one, the lower portions being more completely merged with one another than the upper; but the explanation here adopted appears to be the more natural one.

The five pentagonal plates here regarded as representing the second series are arranged with one side downward and two at the top. They are succeeded by another row of large, apparently loose plates, which probably have two short sides meeting at an obtuse angle below, and two long sides meeting at an acute angle above. They are so arranged that the point of the basal outline fits into the reentrant angle at which two plates of the preceding series meet, and vice versa. The upper portion of the few specimens which have come to hand is obscured, so that I can not tell whether there is an additional series of small oral plates, or whether the series last described continues to the oral aperture.

One or two additional points are necessary to complete the description of this form. One feature of it is the very small size which even the largest of our specimens presents. Another has to do with the upper or roofing portion, whose plate structure is not completely known. This roofing disk is marked by five regular diverging angulations, following the lines of juncture of the upper series of plates. These lines are continuous with very obtuse dihedral angles which are formed longitudinally along the center of the series of pentagonal plates just below. These angular lines, thus almost continuous from top to bottom, are obscure in one specimen, but rather strong in another which is probably immature. The latter possesses the additional character of having a deep dimplelike depression about midway along each of these angles, situated apparently at the apex of each of the pentagonal plates regarded as forming the second series.

One specimen, somewhat differently preserved from the others, shows a feature in them obscured. In this example the outer and inner surfaces alone appear to have been silicified, so that when the specimen was freed by etching, a thin outer and inner shell was left to represent the original thick plates. The outer shell in this case has been broken away and the inner one shows five elliptical elevations radiating from the mouth, apparently corresponding to depressions on the interior.

The only genus with which I can think to compare this curious cystoid is Hypocrinus Beyrich; but it is evidently so distinct from that type that it scarcely seems necessary to point out the differences in detail. If we suppose that there are no little plates around the mouth, and accept the interpretation here adopted as to the basal cup, the cystid is composed of three rings of plates, but the basal ring, instead of consisting of three distinguishable plates, is formed of an uncertain number of completely ankylosed ones, to which, in turn, those of the second series are ankylosed.

I have referred this form to the cystoids instead of the blastoids, because of the absence of large, regular, ambulacral areas and the presence of a large eccentric anal pore. At the same time a certain affinity with the blastoids is shown in the small number of plates, together with their very regular size and arrangement, while the five structures of undetermined function which radiate from the mouth on the inside of the test superficially suggest the ambulacral areas of Pentremites, etc.

While certain features of this species remain unascertained, it is so clearly a new genus, and withal so interesting, that I feel justified in introducing a new generic name. At present I include Cœnocystis, with Hypocrinus, among the Cryptocrinidæ.

Horizon and locality.—Delaware Mountain formation, southern Delaware Mountains, Texas (station 2969).

ECHINOIDEA.

Family ARCHÆOCIDARIDÆ McCoy.

Genus ARCHÆOCIDARIS McCoy.

ARCHÆOCIDARIS CRATIS White?

The Guadalupian specimens referred to this species are fragmentary, representing the median portion of three radioles parallel and almost in contact. They are cylindrical, the largest example having a diameter of about 2 mm., without any perceptible taper. The length of the fragments is only about 11 mm. The spinules are rather small and very scattering, the general appearance suggesting a species closely allied to Archæocidaris cratis.

Horizon and locality.—"Dark limestone," east of Guadalupe Point, Guadalupe Mountains, Texas (station 3762b).

ARCHÆOCIDARIS sp. a.

This very minute form is represented by a single radiole, which has a cylindrical shape, with a diameter of scarcely more than half a millimeter and a length of 5-1/2 mm. It is incomplete at the upper end. There are a few large spinules at relatively long intervals, and the general character is very much as in Archæocidaris cratis, although the size is greatly inferior.

Owing to its minute dimensions and rather imperfectly silicified condition it is impossible to determine definitely the character and distribution of the spinules.

Horizon and locality.—"Dark limestone," Guadalupe Mountains, Texas (station 3762c).

ARCHÆOCIDARIS sp. b.

Pl. XXVII, figs. 18 and 18a.

This form, which is very imperfectly known, is based on two specimens. One of these shows the distal end of the radiole, which is seen to expand rather abruptly from a very slender shaft having a diameter of about three-fourths mm. into a subspherical end which has a diameter of 2 mm. The terminal portion and the shaft adjacent appear to be armed with short spinules.

Associated with the foregoing is the proximal portion of a radiole, showing a long, slender, smooth, cylindrical shaft, which has a diameter of about three-fourths mm., with the usual subterminal collar near the lower end. It is very probable that this and the foregoing fragments belong to the same species, one which is characterized by its small size, long, slender, smooth shaft, and terminal spinose knob.

The Pennsylvanian species which most resembles this is Archæocidaris spiniclavata, which is still very different.

Horizon and locality.—Delaware Mountain formation, southern Delaware Mountains, Texas (station 2969).

ARCHÆOCIDARIS sp. b var.

Associated with the foregoing is the distal portion of a radiole of a very similar type. The terminal knob in this case is relatively larger and somewhat differently shaped. The end is in some degree pointed, and has midway a subangular zone above which it is covered with little spines, but below which it is smooth, like the shaft connected with it.

Horizon and locality.—Delaware Mountain formation, southern Delaware Mountains, Texas (station 2969).

ARCHÆOCIDARIS sp. c.

The material on which this division is based consists of fragments of radioles, some of them representing distal ends and some proximal, but nothing to show the length or character of the shaft between. The proximal ends have the usual configuration, with a subterminal milled collar. The distal end consists of a nearly spherical enlargement covered with little elevations or nodes. Of the two specimens representing this portion the larger has a diameter of 5 mm. One can not, of course, be sure that these fragments belong to the same species, but it seems not unlikely.

This form resembles that which I have designated Archæocidaris sp. b, but is very much larger. In view of this fact, especially since it was found at a different locality and since it is impossible to determine whether it is similar in other respects, such as the arrangement of spinules, etc., it seemed advisable to discriminate them provisionally as distinct species.

Horizon and locality.—"Dark limestone," Pine Spring, Guadalupe Mountains, Texas (station 2930).

ARCHÆOCIDARIS sp. d.

It seems best to group under this title a number of plates, some, of which are associated with the radioles above described and probably belong to the same species; but the preservation of my material is too unsatisfactory to determine with any strong degree of probability, by studying the tubercles and the bases of the radioles, which radioles and plates belong together.

At station 2969, where Archæocidaris sp. b and Archæocidaris sp. b var. were found, five of these plates were obtained, each of them presenting more or less marked differences in size and configuration, so that unless some evidence were available to indicate that such was the case, I would hardly feel justified in referring any two to the same species. A single fragmentary plate from station 3500 agrees fairly well with one of those from station 2969. Five plates collected at station 2930 represent two somewhat distinct types, neither of which has the same characters as the others mentioned.

Consequently, if I were to divide these specimens on intrinsic characters, I would have to recognize seven species of Archæocidaris, based on the configuration of plates; this would demand more space and consideration for my scanty and fragmentary material than it at all merits.

Thus, Archæocidaris sp. d probably comprises more than a single species, possibly as many as seven, some of which, however, it seems very likely belong with the spines that have been entered above under separate titles.

Horizon and locality.—"Dark limestone," Pine Spring, Guadalupe Mountains, Texas (station 2930). Delaware Mountain formation, southern Delaware Mountains, Texas (stations 2969 and 3500).