Systematics and phylogenetic implications of the haplosclerid stromatoporoid Newelliu mira nov. gen. RACHEL WOOD, JOACHIM REITNER AND RONALD R. WEST

LETHAIA Wood, Rachel, Reitner, Joachim 8 West, Ronald R. 1989 01 15: Systematics and phylogenetic impli- cations of the haploslerid stromatoporoid Newellia m’ra nov. gen. Lcthaia, Vol. 22, pp. 85-93. Oslo. ISSN 0024-1164.

The presence of spicules in a Palaeozoic stromatoporoid is here confirmed. Parallelopora mira Newell, 1935 from the Upper Carboniferous of the U.S.A. is redescribed as a calcified haplosclerid sponge with a primary siliceous spicule framework of isodictyally arranged styles, sub-tylostyles and strongyles and a secondary calcareous skeleton of stromatoporoid grade and probable aragonitic original mineralogy. P. m‘ra is placed within a new genus Newellia, and family, the Newellidae. This form is postulated to have possessed large amounts of collagenous organic material which enveloped and bound the spicular framework in place. By the draping outline of the calcareous skeleton around the spicule framework and by analogy with the Recent demosponge genus Vaceletia, the calcareous skeleton is suggested to have formed by the direct mineralization of this collagenous template. Newellia mira nov. gen. is further proposed to constitute a member of a new clack of haplosclerid stromatoporoids. together with Euz- Miella erenoensis (Lower Cretaceous); a clade with some similarity to Recent non-calcified forms, e.g. Adocia. Most notably, the presence of different calcareous skeleton mineralogies and possibly microstructures in these two forms suggests the independent development of a calcareous skeleton at different times within this spicule clade. Demosponges appear to have produced calcareous skeletons independently in many different spicule clades. Calcified demosponges are now known from the Hadro- merida (Lower carboniferous; Upper Cretaceous - Recent), Axinellida (Upper Triassic - Lower Cretaceous; Upper Cretaceous; Recent), Poecilosclerida (Recent) as well as the Haplosclerida (Upper Carboniferous - Lower Cretaceous; Recent). 0 Upper Carboniferous, stromatoporoid, spicules, haplo- sclerid demosponges, calcareous skeleton biomineralization, demosponge clades. polyphyly.

Rachel Wood, Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, U. K . ; Joachim Reimr, lnstihrrfiir Paldontologic der Freien Universitar Berlin, Schwendenersnasse 8, D-1ooO Berlin 33, West Germany; Ronald R. West, Department of Geology, Kansas State University, Manhattan, Kansas 66504, U.S.A.; 2lst January, 1988.

With the finding of spicules within many genera of Mesozoic stromatoporoids (Wood & Reitner 1986; Wood 1987; Reitner 1987a), Palaeozoic and Mesozoic chaetetids (e.g. Gray 1980; Kdmier- czak 1974; Reitner & Engeser 1987) and Meso- zoic sphinctozoans (e.g. Reitner & Engeser 1985; Reitner 1987b, 1988), the poriferan affinity of these previously problematic groups has been confirmed. On the basis of spicule and soft-tissue criteria, the Recent ‘sclerosponges’ have been proved to constitute a polyphyletic assemblage of demosponges and the possession of a calcareous skeleton to be therefore a convergent feature (Vacelet 1985). Accordingly, assuming the same diagnostic priority of spicule type and arrange- ment for fossil forms, former defining charac- teristics of the fossil calcified sponge groups have been found to be invalid too, as they are now shown to consist of assorted calcarean and demo- sponge clades (Wood 1987; Reitner 1987a, 1988).

For example, features such as astrorhizae, dis- sepiments and laminar form thought diagnostic and uniting features of stromatoporoids, are con- vergent ones common to many independent clades of calcified sponges and so regarding mem- bers of all these groups solely within their present discrete taxonomic groupings will obscure true affinities and interrelationships. These previous taxonomic groupings are best redefined as ‘grades’ of organization of the calcareous skeleton (Vacelet 1985; Wood 1987, 1988; Reitner 1987a, 1988). Considering the close similarity of spiculate calcified sponges to non-calcified Recent forms (Vacelet 1985), and the uncertainty of higher taxonomic criteria used in fossil classification sys- tems (Wood 1987), comparison of fossil forms with extant genera and then attempted placement within the Recent poriferan classification is now felt to be their most valid and informative treatment.

86 Rachel Wood and others LETHAlA 22 (1989)

Newell (1935) in his description of the Upper Carboniferous (Mid Pennsylvanian) invertebrate fauna from Kansas and Oklahoma, reported spic- ules from a new species Parallelopora mira, which he assigned to a stromatoporoid genus. These spicules were dismissed, however, by many later workers as being of diagenetic origin. Steam (1972), while agreeing on the presence of spicules, suggested that P. mira did not possess the gallery- crossing dissepiments (filling tissue) and laminar structures which he considered characteristic of stromatoporoids, and as a consequence sediment had infiltrated the open skeletal framework. P. mira was also interpreted by others as being a true calcareous sponge (Fliigel & Fliigel-Kahler 1968). However, Finks (1983) reports that in addition to the non-calcareous spicule mor- phology of P. mira, this form is also faunally. associated with true calcareous sponges whose calcite spicules are not preserved, implying a non- calcareous and therefore siliceous composition for those of P. mira.

Newell’s description of P. mira remains the only undisputed report of a spiculate Palaeozoic stromatoporoid and is therefore of considerable importance in verifying poriferan affinity for some Palaeozoic stromatoporoids and also for attempt- ing to place them in the new systematic framework which is emerging for Mesozoic and Recent cal- cified sponges (Vacelet 1985; Wood 1987; Reitner 1988). However, the taxonomic validity of the taxon Stromatoporoidea cannot strictly be reviewed until the affinity of the type genus Stro- maropora is established.

Family Newellidae nov. fam. Diagnosis. - Calcified haplosclerid with a regular isodictyal arrangement of various megasclere spicules. No microscleres are apparent. The spic- ule lattice forms the framework for the sub- sequent precipitation of a probably aragonitic secondary calcareous skeleton.

Type genus. - Newellia mira nov. gen. (Newell, 1935).

Included genera. - Type genus.

Discussion. - The spiculation of N. mira nov.

gen. is reminiscent of Recent members of the Axinellida, Poecilosclerida and the Haploscler- ida, but this may reflect some of the uncertain or erroneous criteria at present used to discriminate between these Orders. However, the family New- ellidae is placed, with some caution, within the Haplosclerida on the basis of shared spicule type and dimensions (styles, strongyles and sub-tylo- styles; absence of microscleres), spicule arrange- ment (regular and isodictyal, with multispicular tracts) and the inferred quantity and distribution of organic connecting tissue (abundant, with total envelopment of spicule tracts), as shown in Fig. 1.

A new family is erected for the at present unique combination of this spiculation with a postulated aragonitic skeleton. Calcareous skele- ton mineralogy and microstructural type (where known) are thus taken to be diagnostic criteria of familial rank when used in conjunction with spicule information.

Newellia nov. gen. Derivation of name. - In honour of Norman D. Newell who discovered and first described this material.

Diagnosis. - Newellidid with a spicule skeleton of radial plumose megasclere tracts (styles, strongyles and sub-tylostyles) and transversely arranged singular or bundles of shorter strongyles forming lateral connections. The calcareous skeleton appears to be draped in a meniscus-like arrangement around the spicule framework.

Remarks. - Newell (1935) assigned this species to Parallelopora following the generic descriptions of Nicholson (1886) and Bargatzky (1881). although he recognized that the genus was poorly understood at that time.

The type species, P. ostiolata Bargatzky, 1881 possesses abundant tabular secondary filling tissue, tabulate astrorhizal canals and a ‘porous’ skeletal microstructure. Since ‘Purallelopora’ mira displays none of these defining features and possesses additional unique ones, it is clearly not con-generic with P. ostiolata. Neither can it be referred to any other existing genus, and so a new genus must be erected to accommodate it.

LETHAIA 22 (1989) Haplosclerid stromatoporoids 87

Newellla mlra n0v.g.n.

U.Carboniferous

a: style

b: subtylostyle

Fig. 1. Comparison a the

f

Euzkadlella Adocie L.Cretaceous Recent

c: atrongyle

d: oxea

e: spicule framework

1: collagen (Inferred In fossil forma)

Calclflbroaaonaia

Recent

g: calcareoua skeleton

srm and arrangement of skeletal parts in discussed haploscleri jemosponges. Dotted line marks exoDinacoderm in the Recent non-calcified form (Adocia). Partially after Levi (1973) and Reitner (1987a). Full explanation in text. Scale bar = 100 p.

Newellia mira (Newell, 1935) nov. gen . Figs. 2 4

v* 1935 Parallelopora mira Newell, p. 341-3, PI. 34, Figs. 6-10.

Emended diagnosis. - Newellia with no filling tissue.

Included species. - Type species.

Type material. - About 40 worn fragments (1- 5 cm diameter) and associated thin-sections, Base of the Vilas shale at the railroad quarry near

the SW.1/4 sec. 11, T.20 S., R. 19E., Anderson County, Kansas and from the same horizon on the highway 2 miles north of Garnett, Kansas (Middle-Pennsylvanian, Upper Carboniferous). Holotype no. 58231; Paratype nos. 59758-59777, 59779,59769,59743-59750,58233,58232,58234. Types held at the Museum of Invertebrate Paleontology at the University of Kansas and supplementary types at the Peabody Museum, Yale University.

Description. - Newellia mira nov. gen. possesses a massive, hemispherical, nodular or encrusting skeleton and in cases where known, a small sur- face attachment. There is no apparent basal epitheca. Weathered tangential surfaces show a

88 Rachel Wood and others LETHAIA 22 (1989)

Fig. 2. Spicuk arrangement in Nemllio mira nov. gcn. (Newell. 1935) from chc Upper Carboniferous of Anderson County. Kansas, U.S.A. Paratype, University of Kansas no. 59769. Scanning electron photomicrographs. 0 A. Tangential section showing overall skeletal organization. Scale bar = 100 pn. 0 B. Detail of Fig. A, showing pitted spicules. Scale bar = 30 pn. 0 C. Detail of transverse strongyles and meniscus form of the calcareous skeleton around the spicule framework (arrowed). Scale bar = 30 pn. 0 D. Longitudinal section showing detail of isodictyd arrangement. Scale bar = 3 0 ~ .

LETHAIA 22 (1989) Hapbsclerid stromatoporoidr 89

Fig. 3. Spicule arrangement in Neweuio miro nov. gen. (Newell, 1935) b m the Upper carboniferous of Anderson County, Kansas, U.S.A. (Figs. A, B, D) and comparison with Euz&udjeUa mmnsis Reitner, 1987 from the Lower Cretaceous of North Spain (Fig. C). Light photomicrographs. 0 A, B, D. Newelliamira nov. gen. Paratype. Universityof Kansas no. 59769.0 A. Longitudinal section showing the overall skeletal arrangement of plumose megasclere tracts forming broad columns with foramina. No calcareous skeleton microstructure is discernible. Scale bar = 100 pm. 0 B. Detail of Fig. A. showing style megascleres and smaller strongyles forming transverse connections in an isodictyal arrangement. Scale bar = 30 pn. 0 C. Longitudinal section of Euzkadiella erenoensis showing similar types and arrangement of megasclere spicules within broad columns with a spherulitic calcareous skeleton. Paratype no. I P N 86/1. lnstitut fih Palaontologie der Freien UniveaitHt Berlin. Scale bar = 100 pn. 0 D. Transverse section of N. mira showing circular spicule cross-sections distributed throughout the column. Scale bar = 30 p.

90 Rachel Wood and others LETHAlA 22 (1989)

ton of continuous broad columns (60-120 pm diameter) and transverse connections (30-70 pm diameter, Figs. 3A and 2A). The columns enclose circular or irregular foramina, ranging from 100pm to l m m diameter (Fig. 3A). No astro- rhizal canals are expressed within the calcareous skeleton and no filling tissue is present.

meandriform pattern of elements. Weathered longitudinal surfaces show latilaminae, spaced 1- 3mm apart, but as noted by Newell these give no apparent expression or explanation in thin- section.

The spicules are preserved as both mono- and multicrystalline calcite and SEM examination shows them to be frequently diagenetically pitted as noted in other Recent and fossil demosponge spicules enclosed within a calcareous skeleton (Fig. 2B). No axial canals have been found. In transverse section the spicules are conspicuous as clear circular areas distributed throughout the skeletal elements (Fig. 3D). The spicules are straight to slightly curved styles (110-150 x 10- 15 pm, Fig. 4A), sub-tylostyles (115-150 x 10- 15 pm, Fig. 4B) or strongyles (60-120 x 5-10 pm, Fig. 4C). In longitudinal section they form radial tracts, where the spicules are arranged in quite closely packed but very low-angle upwardly repeated plumules, together with singular or bundles of transversely arranged smaller stron- gyle spicules (80 x 7 pm average, Fig. 2C) form- ing a regular isodictyal arrangement (Figs. 3B and 2D). The calcareous skeletal elements are pigmented by ‘dark’ coloured specks and consist of microgranular spar (Fig. 3A). No traces of original microstructural textures are discernible, but the calcareous tissue boundary drapes around the whole spicular framework, especially around those spicules which extend beyond the general skeletal boundary (Fig. 2C). The isodictyal spic- ule framework thus produces a calcareous skele-

Distribution. - North America (Kansas). Upper Carboniferous (Middle Pennsylvanian).

Mineralogy and biomineralization According to Sandberg (1984) and others, the presence of ‘dark’ inclusions (possible decom- posed organic remains) and a totally obliterated microstructure in calcareous skeletons are indica- tive of original aragonitic mineralogy (Fig, 3A). The meniscus-like arrangement of the calcareous skeleton draped over a primary spicule frame- work has also been noted in the axinellid stro- matoporoid Actinostromarianina lecompti (Wood & Reitner 1986; Wood 1987), which has an irregular microstructure (Fig. 5). However, in contrast to the microgranular spar skeleton of N . mira nov. gen., the calcareous skeleton of A . lecompti is preserved as micrite. This may be a possible indication of the differing original min- eralogies of these two forms. In A. lecompti, a spicule coating of collagenous material has been postulated, which subsequently became miner- alized to form the irregular calcareous skeleton

Fig. 4. Spicule types found in Newellia mira nov. gen. (Newell, 1935) from the Upper Carboniferous of Anderson County, Kansas, U.S.A. Paratype University of Kansas no. 59169. Scale bar = 30 pm. Scanning electron photomicrographs. 0 A. Style. 0 B. Sub- tylostyle. 0 C. Strongyle.

LETHAIA 22 (1989) Haplosclerid stromatoporoids 91

Fig. 5. Actinarrromahmi~ Iccompti Hudson, 1955 from the Upper Kimmeridgian of Alam Abayadh, North Yemen, BMNH H4608a. showing the meniscus-like arrangement of the irregular calcareous skeleton draping around the primary spicule frame- work (arrowed). Scale bar = 100 p.

(Wood 1987, 1988). Likewise, a similar arrange- ment of collagenous tissue, method of biomin- eralization and hence possibly microstructural type can be suggested for N . mira nov. gen. A modem analogue for this biomineralization mech- anism is the ceractinomorph demosponge Vace- letia crypta, where although a spicule framework is absent an irregular aragonitic calcareous skele- ton is formed by direct mineralization of col- lagenous plates (Vacelet 1985).

Comparison of Neweffia mira nov. gen. and phylogenetic implications Newel1 (1935) recognized that Newellia mira nov. gen. incorporated both stromatoporoid and pori- feran features, but did not pursue the discussions.

No Recent forms are known to the authors which combine the three megasclere types found in Newellia nov. gen., but the spicule arrangement of N. mira nov. gen. is similar to that of Adocia, a Recent non-calcified haplosclerid within the family Adociidae (Fig. 1). This species possesses an isodictyal unispicular skeleton forming plu- mose tracts of closely packed oxeas, with identical

single oxea forming transverse connections at intervals. The whole spicule skeleton is enmeshed in connective spongin, forming an ascending, reticulate and ramifying overall organization.

However, N . mira nov. gen. shows most simi- larity to the calcified haplosclerid demosponge, Euzkadiella erenoensis from the Lower Cre- taceous of North Spain (Reitner 1987a) (Fig. 3C) and to a lesser extent the Recent form Calci- fibrospongia actinostromarioides (Fig. 1). In par- ticular, E. erenoensis shares the same spicule types and arrangement of short strongyles (90 x 6 pm compared to 80 x 7 pm for N. mira nov. gen.) forming transverse skeletal con- nections between the radial tracts. However, although the spicule frameworks are very similar, these two comparative forms have spherulitic cal- careous skeletons of low-magnesium calcitic and aragonite, respectively (see Reitner 1987a).

N . mira nov. gen. at an organizational grade of the calcareous skeleton thus constitutes a spi- culate stromatoporoid, but when viewed together with calcified and non-calcified demosponges, it can best be regarded as a member of a new stromatoporoid-grade clade, with two now known from the Haploxlerida: Neweffia mira nov. gen. (Lower Carboniferous) and Eurkadiella ereno- ensis (Lower Cretaceous) forming one spicule clade and Calcifibrospongia actinostromarioides with its spicular skeleton of strongyles only, repre- senting a second (Fig. 6). It is interesting to note that in contrast to other calcified demosponges, none of the known calcified haplosclerids pos- sesses secondary filling tissue, but at present it is not clear whether this feature should be given any high-level taxonomic significance.

One must conclude from differences in min- eralogy and possibly microstructural type, and therefore biomineralization mechanisms, that the calcified skeleton has not only been independently gained in these two spicule clades, but also inde- pendently acquired by Newellia mira nov. gen. and Euzkadiella erenoensis within the same clade. This conclusion and the ability of the Recent genus Merlia to produce a facultative calcareous skeleton, support the notion suggested by Vacelet (1985) that demosponges can produce calcareous skeletons with relative ease.

The determination of this further long-ranging calcified sponge clade, in forms corresponding to the stromatoporoid grade of organization, clearly shows that it is no longer prudent to continue the total differentiation between Palaeozoic and

92 Rachel Wood and others LETHAIA 22 (1989)

HAPLOSCLERIDA HADROMERIDA

RECENT

AXINELLIDA -0

TERTIARV

CRETACEOUS

s! PERMIAN

y?

c s

31 -9-

C-J . ? f

? sp--’

POECILOSCLERIDA 4-

RECENT (non-calclflod)

0 RECENT (colclflod)

0 FOSSIL

Taxonomlc soparrtlon of Rocont forms :

0: gonus

s: Sp0cl.s

Qrsdms o f calearsous rkolotal organlsatlon :

5: STROMATOPOROID

C: CHAETETID

Sp:SPHINCTOZOID

Fig. 6. The temporal distribution of known calcified demosponges. including some determined clades. within four Recent demosponge orders. The Occurrence and grade of calcareous skeleton development is shown within these orders. Spicule clades are defined by Recent noncalcified forms which show close relationship to Recent calcified forms. The close affinity between non- calcified and calcified forms is shown by connected dotted lines and an indication of taxonomic separation. Unconnected dotted tines indicate aflinity to order level only. Additional fossil calcified demosponges are known from the Tetractinomorpha, Ceractinomorpha and Choristida, but the data are not shown 8s their more precise taxonomic placement is unclear. Data from Kahieraak (1974), Gray (1980). Reitner d Engeser (1985. 1981), Vaalct (1985), Wood (1987). Reitner (1987a, 1987b) and Wood & Reitner (1988). plus work in progress.

Mesozoic stromatoporoids, as the presence of a clade which cross-cuts the time boundary and proported ‘gap’ indicates this to be, at least par- tially, an erroneous separation. Calcified demo- sponge clades are now known from the Hadro- merida (Lower Carboniferous; Upper Creta- ceous- Recent; see Gray 1980; Reitner & Engeser 1987), Axinellida (Upper Triassic - Lower Cretaceous; Upper Cretaceous; Recent; see Wood 1987; Wood & Reitner 1988), Poecilo- sclerida (Recent; see Vacelet 1985) as well as the Haploxlerida (Upper Carboniferous - Lower Cretaceous; Recent; this work; Vacelet 1985) as represented in Fig. 6.

It remains to discern the factors and mech- anisms responsible for the development of a calcareous skeleton within demosponges. Inde- pendent development at different times within

the same clade points to the probable mediation of environmental or ecological pressures. There- fore, possession of a calcareous skeleton may not always be a plesiomorphic feature as previously suggested (Vacelet 1985).

Conclusions (1) Neweflia mira nov. gen. (Newell, 1935) from the Upper Carboniferous of Kansas, U.S.A. is redescribed as a calcified haplosclerid sponge with a primary siliceous spicule framework of iso- dictyally arranged styles, sub-tylostyles and strongyles, and a secondary aragonitic skeleton of stromatoporoid grade.

(2) N . mira nov. gen. is placed in a new family, the Newellidae.

LETHAIA 22 (1989) Haplosclerid stromatoporoids 93

(3) N . mira nov. gen. is suggested to have had large amounts of collagenous organic skeleton which enveloped and bound the spicular framework.

(4) The biomineralization mechanism of the cal- careous skeleton is postulated to have been direct calcitization of the collagenous fibres, like that of the Recent genus Vaceletia.

( 5 ) N. mira nov. gen. constitutes a member of a new clade of calcified haplosclerids, together with Euzkadiella erenoensis (Lower Cretaceous).

(6) This clade crosses the supposed ‘gap’ between Palaeozoic and Mesozoic stromatoporoids, thus questioning the total systematic separation of these two groupings.

(7) Demosponges appear to produce calcareous skeletons with relative ease.

Acknowledgements. - This work was funded by the Royal Society European Exchange Programme (R.W.) and the Deutsche Forschungsgemeinschaft (J.R., no. RE 665, 1-1). which are gratefully acknowledged. J.R. wishes to thank Frau St raw for technical support on the SEM. The Museum of Invertebrate Paleontology at the University of Kansas is thanked for the loan, and permission to section paratype material.

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Reitner, J. 1987b: A new calcitic sphinctozoan sponge belonging to the Dcmospongiae from the Cassian Formation (Lower Carnian; Dolomites, Northern Italy) and its phylogenetic relationship. Geobios 20, 571-589.

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Wood, R. & Reitner, J. 1988: The ‘chaetetid‘ demosponge Srromatoerinello irregularis nov. gen. (MICHELIN) and its systematic implications. Neues lahrbuch f i r Geologie und Palaontologie, Abhandlungen In. In press.