MarcusFossils Posted August 8, 2016 Share Posted August 8, 2016 (edited) Hello all, I recently purchased a very nice sponge fossil from the Chengjiang Formation, called Leptomitus teretiusculus. I can't find any information on it though, and I'm hoping you guys can help me out (piranha & doushantuo, you guys especially ) Thank you! Edited August 8, 2016 by MarcusFossils Website: https://www.instagram.com/paleo_archives/ --------------------------------------------------------------------------- “It is by no means an irrational fancy that, in a future existence, we shall look upon what we think our present existence, as a dream.” ― Edgar Allan Poe Link to comment Share on other sites More sharing options...
Guguita2104 Posted August 8, 2016 Share Posted August 8, 2016 (edited) Hi Marcus!Beautiful critter ! For what I read, the genus Leptomitus belongs to Leptomitidae family- Protomonaxonida order - Demospongiae class. Demosponges are well-known among paleontologists and biologists, because their skeletons ( however there are specimens of this class that don't present skeleton) are constituted of spicules ,or of an organic substance ("spongin) ,or even of both. Leptomitus was sessile and filter-feeder (feeding on plankton) and probably inhabited Cambrian tropical/subtropical maritime environments and whose existence range started at 516.0 M.of years and ended at 513.0M of years. Feel free to correct me if there is anything wrong (it was the fist time I heard about this genus ) Links: http://fossilworks.org/bridge.pl?a=taxonInfo&taxon_no=206763 http://wzar.unizar.es/murero/activos/pdfs/2007_GarciaBellidoetal_Palaeontology.pdf Regards, Edited August 8, 2016 by Guguita2104 2 Link to comment Share on other sites More sharing options...
MarcusFossils Posted August 8, 2016 Author Share Posted August 8, 2016 (edited) Thank you Gugita! This is exactly the information I was looking for The reason I found nothing is that I had googled "Leptomitus terretiusculus", with that extra "r" Edited August 8, 2016 by MarcusFossils Website: https://www.instagram.com/paleo_archives/ --------------------------------------------------------------------------- “It is by no means an irrational fancy that, in a future existence, we shall look upon what we think our present existence, as a dream.” ― Edgar Allan Poe Link to comment Share on other sites More sharing options...
piranha Posted August 8, 2016 Share Posted August 8, 2016 Original description Chen et al. 1989: Family Leptomitidae de Laubenfels, 1955 Genus Leptomitus Walcott, 1886 Type species: Leptomitus zitteli Walcott, 1886 Leptomitus teretiusculus sp. nov. (Pl.Ⅰ, fig. 4; Pl.Ⅴ, fig. 1—8; Pl. Ⅵ, fig. 2; text-fig. 1) Material: 14 specimens available for the present study, all compressed. Diagnosis: Tubular, thin-walled sponges with double-layered skeleton composed of monaxons, ranging up to ll0mm in length and approximately 12mm in flattened width. Outer layer of skeleton consisting of a vertical thatch of fine monaxons and inserted vertical rods composed of large oxeas in echelon structure; inner layer consisting of unbounded monaxons approximately 0.25mm apart. Description: Holotype (Cat. No.108480) being a nearly complete specimen, 80mm long, with a narrow base 1mm wide, which expands gradually upwards to a maximum flattened width of approximately 6mm at height of 63 mm; remaining part of the specimen tubular. Oscular margin unpreserved. Skeletal net composed of three size series of monaxons. Coarse oxeas making up the distinct rods which extend vertically to the full length of the sponge. Oxeas 3—4mm long, and 0.1mm across. Rods 0.16mm apart in the upper part where 27—28 of them appear, and 0.08 mm apart near the base of the specimen where they are reduced to 20. Interspaces of rods filled with the smallest monaxons which are generally poorly preserved, approximately 0.2—0.3mm long, and 0.01mm across in size as observed from Cat. No. 108482. Horizontal monaxons of inner layer slightly coarser than the fine monaxons of the outer layer, approximately 0.5mm long, 0.02mm across, and 0.25mm apart. Discussion: This new taxon bears a general resemblance to Leptomitus lineatus (Walcott, 1920). But in the former the sizes of sponges and spicules are much smaller. Chen, J.Y., Hou, X.G., & Lu, H.Z. (1989) Lower Cambrian leptomitids (Demospongea), Chengjiang, Yunnan. Acta Palaeontologica Sinica, 28:17-31 Updated description Rigby & Hou 1995: Rigby, J.K., & Hou, X.G. 1995 Lower Cambrian demosponges and hexactinellid sponges from Yunnan, China. Journal of Paleontology, 69(6):1009-1019 figure & text from: Hou, X.G., Aldridge, R.J., Bergström, J., Siveter, David-J., Siveter, Derek-J & Feng X.H. (2004) The Cambrian Fossils of Chengjiang, China: The Flowering of Early Animal Life. Blackwell Scientific Publishing, 233 pp. L. teretiusculus is a moderately common, thin-walled sponge. Specimens range up to 110 mm long and about 12 mm wide. The body is very elongate, tube-shaped and composed of two skeletal layers, each with single-axis (monaxon) spicules. The dominant, outer layer consists of a vertical thatch of fine and larger spicules, which in some specimens are slightly smaller in the lower half of the skeleton. The inner skeletal layer consists of tiny, more poorly defined, horizontally arranged spicules. A short fringe of spicules extends beyond the oscular margin. Leptomitus is the type genus of the Family Leptomitidae and is generally recognized to represent the stock from which a variety of demosponges evolved (Rigby 1986). In life L. teretiusculus was attached to the substrate by a relatively small surface area, straining food from water pumped through its wall. L. teretiusculus is known only from the Chengjiang biota. A larger Leptomitus species occurs in the Burgess Shale (Rigby 1986). Congeneric material has also been reported from the Lower and Middle Cambrian of Guizhou Province, China (Zhao et al. 1999a, Zhao et al. 1999c). 4 Link to comment Share on other sites More sharing options...
MarcusFossils Posted August 8, 2016 Author Share Posted August 8, 2016 Thanks everyone, this is great Website: https://www.instagram.com/paleo_archives/ --------------------------------------------------------------------------- “It is by no means an irrational fancy that, in a future existence, we shall look upon what we think our present existence, as a dream.” ― Edgar Allan Poe Link to comment Share on other sites More sharing options...
ElToro Posted October 27, 2017 Share Posted October 27, 2017 Hi guys! I know this is an old thread but I'd like a little input. A mate has a fossil that he believes is Yunnanozoon or Leptomitos. It looks like Yunnanozoon to me but I can't find many pics of the Leptomitos. What y'all think? Also, the surface seems to be slightly striated which I find weird... "That belongs in a museum!" - Indiana Jones Link to comment Share on other sites More sharing options...
MarcusFossils Posted October 27, 2017 Author Share Posted October 27, 2017 Hi Eltoro, It's definitely not a Yunnanozoon, I'd go with Leptomitus as an ID. Cheers, Marc Website: https://www.instagram.com/paleo_archives/ --------------------------------------------------------------------------- “It is by no means an irrational fancy that, in a future existence, we shall look upon what we think our present existence, as a dream.” ― Edgar Allan Poe Link to comment Share on other sites More sharing options...
ElToro Posted October 27, 2017 Share Posted October 27, 2017 Hi Marcus, You sure? The pic is upside down if it is a Yunnanozoon. So this is just a common sponge? Nothing exciting or rare? I can see how these striations are similar to pics of the Leptomitus. "That belongs in a museum!" - Indiana Jones Link to comment Share on other sites More sharing options...
MarcusFossils Posted October 27, 2017 Author Share Posted October 27, 2017 1 minute ago, ElToro said: Hi Marcus, You sure? The pic is upside down if it is a Yunnanozoon. So this is just a common sponge? Nothing exciting or rare? I can see how these striations are similar to pics of the Leptomitus. Leptomitus are still fairly rare! But the striations have me 100% convinced it's Leptomitus. Website: https://www.instagram.com/paleo_archives/ --------------------------------------------------------------------------- “It is by no means an irrational fancy that, in a future existence, we shall look upon what we think our present existence, as a dream.” ― Edgar Allan Poe Link to comment Share on other sites More sharing options...
doushantuo Posted October 28, 2017 Share Posted October 28, 2017 Leptomitus as Marcusfossils says (Garcia-Bellido,2007/Palaeontology) 1 Link to comment Share on other sites More sharing options...
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