The oldest labechiid stromatoporoids from intraskeletal crypts in lithistid sponge-Calathiumreefs

Lethaia ◽  
2016 ◽  
Vol 50 (1) ◽  
pp. 140-148 ◽  
Author(s):  
Qijian Li ◽  
Yue Li ◽  
Wolfgang Kiessling
Keyword(s):  
1991 ◽  
Vol 28 (12) ◽  
pp. 2042-2061 ◽  
Author(s):  
Tim A. de Freitas

Abundant hexactinellid and lithistid sponges occur in Ludlow (Silurian) platform slope strata of the Cape Phillips Formation, Canadian Arctic Islands. The following are new: in the Anthaspidellidae Miller, 1889, rhodesispongia simplex n.gen and sp., Climacospongia snowblindella n.sp., and Climacospongia undulata n.sp.; in the Sphaerocladina Schrammen, 1910, Caryospongia tuberosa n.sp.; in the Hexactinellida Schmidt, 1870 Malumispongium? cornwallisi n.sp., of the monospecific superfamily Malumispongium Rigby, 1967. Other previously described sponges recognized in the study assemblage include Hindia sphaeroidalis Duncan, 1879 and Caryospongia juglans Rauff, 1894. These occur in association with abundant Archaeoscyphia sp. in thin, laterally extensive lithistid sponge biostromes which throve on platform slope sediments during the Late Silurian. Based on the dominant dendroclone forms in the skeletons of these and other genera, Anthaspidellidae can be divided informally into two groups: (i) the polyclonids, possessing complex skeletons built of variable dendroclones types, including I-, X-, and Y-shape dendroclones, and accessory spicules, including rhizoclones, chiastoclones, and monactines; and (ii) the monoclonids, possessing simpler parenchymal canal systems and skeletons constructed mainly of I-shaped (amphiarborescent) dendroclones and lacking accessory spicules. The classification, based chiefly on skeletal architecture, suggests two main evolutionary trends in the family. The monoclonids generally maintained structural simplicity, inherited from the probable ancestral monactinellid, whereas the polyclonids evolved a varied and complex skeletal architecture that was more successful.


1994 ◽  
Vol 116 (17) ◽  
pp. 7631-7636 ◽  
Author(s):  
Carole A. Bewley ◽  
Cecile Debitus ◽  
D. John Faulkner

1989 ◽  
Vol 63 (6) ◽  
pp. 819-838 ◽  
Author(s):  
Owen A. Dixon

Specimens representingHeliolites diligensBondarenko, 1966,H.aff.H. luxarboreusYang, 1978, andH. tchernysheviBondarenko, 1966, are common andHeliolitessp. andStelliporellasp. are rare in diverse coral assemblages associated with lithistid sponge reefs in deep shelf or ramp limestone facies of the Douro Formation.Heliolites diligens, a more widely adapted, possibly “opportunist” species, occurs abundantly in lower diversity stromatoporoid/coral assemblages from nonreefal, shallower shelf limestone facies. Detailed systematic study of approximately contemporaneous populations of these Ludlovian heliolitid species shows that all are morphologically variable; assessment of this variability qualitatively and quantitatively is critical to species definition and recognition.Heliolites diligensis the most variable, with wide intercolony variation in septal development, corallite wall configuration, and spacing of horizontal skeletal elements. This apparently represents morphological plasticity rather than differences that can be ascribed to distinct species. Conspecificity of the more extreme and dissimilar variants can be inferred from study of large assemblages of coeval specimens. The other species, with more narrowly defined, discrete variation fields, are more readily distinguished from each other.


Lethaia ◽  
2000 ◽  
Vol 33 (3) ◽  
pp. 214-235 ◽  
Author(s):  
Erle G. Kauffman ◽  
DIETRICH HERM ◽  
CLAUDIA C. JOHNSON ◽  
PETER HARRIES ◽  
RICHARD HO éFLING
Keyword(s):  

1989 ◽  
Vol 63 (5) ◽  
pp. 550-553 ◽  
Author(s):  
J. Keith Rigby ◽  
Edward I. Leith

The new thin-walled vasiform dictyospongid hexactinellid, Tiddalickia manitobensis, is described from the Ordovician Red River Formation at McBeth Point on Lake Winnipeg, Manitoba. Vertical spicule bundles are an outer? part of the wall and horizontal spicule bundles an inner? different level within the wall. Bundle quadrules are only half the size of those in Tiddalickia quadrata Rigby and Webby, 1988. A complete anthaspidellid lithistid, Aulocopella winnipegensis Rauff, 1895, is described from a glacial erratic recovered from near Reston, Manitoba.


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