Trab

A trab is a structural element within a sponge formed by the fusion of dendroclones.

In the Anthaspidellidae, when spicules (usually dendroclones) connect at their tips to form a ladder-like structure, trabs may be formed.¹ Oxeas are sometimes employed in the central rod.¹² Trabs have a feather-like structure, or may form rods.¹³

Trabs are usually regularly spaced, usually at sub-millimetric intervals.¹ Further dendroclones may interconnect adjacent trabs, forming ladder-like structures.²

The presence and alignment of trabs is often related to the internal structure of canals within sponges.⁴

References

Kruse, P. (1983). "Middle Cambrian 'Archaeocyathus' from the Georgina Basin is an anthaspidellid sponge". Alcheringa: An Australasian Journal of Palaeontology. 7 (1): 49–58. Bibcode:1983Alch....7...49K. doi:10.1080/03115518308619633.
Bingli, L.; Rigby, J. K.; Zhongde, Z. (2003). "Middle Ordovician Lithistid Sponges from the Bachu-Kalpin Area, Xinjiang, Northwestern China". Journal of Paleontology. 77 (3). Paleontological Society: 430–441. doi:10.1666/0022-3360(2003)077<0430:MOLSFT>2.0.CO;2. JSTOR 4094792.
Rigby, J. Keith (1973). "A New Anthaspidellid Sponge from the Silurian of Lake Timiskaming, Quebec". Journal of Paleontology. 47 (4). Paleontological Society: 801–804. JSTOR 1303055.
Rigby, J.K.; Collins, D. (2004). Sponges of the Middle Cambrian Burgess Shale and Stephen Formations. Royal Ontario Museum Contributions in Science. Vol. 1. Royal Ontario Museum.

[Kruse-1] Kruse, P. (1983). "Middle Cambrian 'Archaeocyathus' from the Georgina Basin is an anthaspidellid sponge". Alcheringa: An Australasian Journal of Palaeontology. 7 (1): 49–58. Bibcode:1983Alch....7...49K. doi:10.1080/03115518308619633.

[Liu-2] Bingli, L.; Rigby, J. K.; Zhongde, Z. (2003). "Middle Ordovician Lithistid Sponges from the Bachu-Kalpin Area, Xinjiang, Northwestern China". Journal of Paleontology. 77 (3). Paleontological Society: 430–441. doi:10.1666/0022-3360(2003)077<0430:MOLSFT>2.0.CO;2. JSTOR 4094792.

[3] Rigby, J. Keith (1973). "A New Anthaspidellid Sponge from the Silurian of Lake Timiskaming, Quebec". Journal of Paleontology. 47 (4). Paleontological Society: 801–804. JSTOR 1303055.

[Rigby2004-4] Rigby, J.K.; Collins, D. (2004). Sponges of the Middle Cambrian Burgess Shale and Stephen Formations. Royal Ontario Museum Contributions in Science. Vol. 1. Royal Ontario Museum.

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