Porifera

Stromatoporoidea

Labechiida

Unknown

Labechiidae

Labechia Nestor, Copper, & STOCK, 2010, p. 59

Monticularia conferta LONSDALE, 1839, p. 688, pl. 16,5,5a; M; only external surfaces of one (or possibly two) of LonSDale’s syntypes from Benthall Edge and/or Gleedon Hill were illustrated initially, and that material is presumed lost; then EDWarDS and Haime (1855, p. 269, pl. 62,6,6a–c) figured external surfaces of a topotype from Benthall Edge (specimen placed in MNHM, Paris); later, SMITH (1932, pl. 1,1–2) chose a specimen from Wenlock Limestone, Benthall Edge as the neotype (BGS no. 28183, Nottingham), because it had been presented originally by R. I. Murchison to the Geological Society of London, and SMITH thought it might have represented one of LONSDALE’s syntypes; however SMITH’s neotype has remained unsectioned and unstudied, hence it is probably invalidly designated; Nicholson (1886a, 1886c, 1889, 1891a) was the first to study thin sections based on specimens from Dudley, Benthall, and Ironbridge, including the Dudley specimen NHM P.5984, with nine thin sections (no.264, 264a–h) apparently cut from it, but that specimen is missing

Fig. 392a–b.*L. conferta (Lonsdale), Wenlock Limestone, Dudley, England, X5, NHM P.5984, Nicholson’s thin sections no. 264, 264g; a, longitudinal section showing solid, vertically aligned pillars with thickening close to skeletal base and in places a cone-in-cone appearance, as well as well-imbricated series of upwardly convex cyst plates; note also thin film of dark matter (possibly originally sediment) and a small, dome-like, growth-banded bryozoan colony, near bottom center of field of view (Webby, 2012c; Nicholson’s thin section 264g, rephotographed by Webby in 1989); b, tangential section (part of Nicholson thin section no. 264) showing round pillars, some with lighter- or darker-colored centers where apices of compositionally distinct cone-in-cone layers are intersected, and cyst plates are represented by offsets between pillars (Webby, 2012c; part of Nicholson’s thin section 264, rephotographed by Webby in 1989).——Fig. 392c–e. L. conferta (LonSDale), probably from same Dudley locality and stratigraphic level; specimen AMF.134351, originally presented by T. W. Edgeworth David to Sydney University, ×5 (Webby, 2012c); c, tangential section showing rounded pillars with a wide range of diameters; d, longitudinal section showing successive latilaminae and pillars extending as papillae into darker sedimentary material above successive tops of latilaminae; e, longitudinal section showing initial latilaminate growth over an uneven (possibly uncon- solidated) substrate, and a small cavity (now represented as a calcite-spar–filled space) at the base that possibly formed when the initial growth spread (and uparched) over the substrate; note well-developed papillae occur at tops of both latilaminae (papillae on terminal surface of this specimen are illustrated in Fig. 316.1) (Webby, 2012c).

Canada (Quebec), China (Shandong), ?Korea, USA (New York, Vermont), Darriwilian; Australia (Tasmania), Canada (Ontario, Akpatok Island, Newfoundland), China (Xinjiang), Mongolia, Norway, Kazakhstan, Russia (Urals, Gornaya Shoriya, Tuva), Scotland, USA (Alabama, Tennessee, Virginia, Kentucky, Indiana, Ohio, Michigan), Sandbian–Katian; China (Guizhou), Estonia, Russia (Siberian platform, Tuva), lower Silurian; Central Asia, England, Sweden (Gotland), Russia (Russian and Siberian platforms, Urals, Kolyma, Tuva), Ukraine (Podolia), USA (Indiana), middle Silurian; Russia (Siberian platform, Urals, Altai Mountains), Sweden (Gotland), upper Silurian; Canada (Ellesmere Island), China (Sichuan, Guizhou, Hunan), Russia (Kolyma), Lower Devonian; Canada (Alberta), Russia (Russian platform, Novaya Zemlya, Vaigach Island, Urals, northern Caucasus), Ukraine (Donets basin), Frasnian Famennian.

Middle Ordovician (Darriwilian)

Darriwilian

0

469.42

Upper Devonian (Famennian)

Famennian

100

359.3

Skeleton composed of long, stout, rounded pillars to more sporadically developed, less continuous, small pillars, and an intricate mesh of cyst plates with moderately upward convexity; pillars may terminate as papillae on upper surface and may show upwardly converging cone-in-cone banding in longitudinal section (concentric rings in tangential section). [The genus includes a wide range of longitudinal structural elements, from those with a patchy development of small short pillars that are grouped in the Labechia prima species group to those with long and stout, rounded pillars of the L. conferta species group (WeBBy, 1979a, p. 90). Representatives of the L. prima group commonly show aligned rows of small to moderately sized, low-convexity cyst plates that, in places, alternate with irregularly laterally continuous bands of spar with loss of original structural elements, perhaps because they were originally poorly calcified bands; finer-textured Stratodictyon WeBBy, 1969, exhibits similar patterns of aligned rows of low-convexity cyst plates. Members of the L. conferta group, on the other hand, have interspaces between pillars filled by a meshwork of cysts that are characteristically coarser, more vesicular and more imbricated.]

Nestor, Heldur, Paul Copper, & C. W. Stock. 2010. Late Ordovician and Early Silurian Stromatoporoid Sponges from Anticosti Island, Eastern Canada: Crossing the O/S Mass Extinction Boundary. National Research Council Research Press. Ottawa, Canada. 163 p., 28 fig., 28 pl.