Chaetocladus

Chaetocladus Temporal range: Middle Ordovician - Devonian[1]
The holotype of Chaetocladus plumula (USNM 41 137, from LoDuca 1997)
Scientific classification
Kingdom:	Plantae
Phylum:	Chlorophyta
Class:	Ulvophyceae
Order:	Dasycladales
Family:	Triploporellaceae
Tribe:	Salpingoporelleae
Genus:	Chaetocladus Whitfield 1894 emend LoDuca 1997
Species
C. gracilis Kenrick & Vither 2006 C. ruedemanni LoDuca 1997 C. dubius LoDuca 1997 C. plumula Whitfield 1894 C. hefteri Kra¨usel and Weyland, 1962

Chaetocladus is a non-calcifying genus of unicellular green algae known from the Upper Silurian.

Morphology

Chaetocladus thalli range from 2–6 cm in height and average 1 cm in diameter.^[2] They comprise a parallel-sided, unbranching axis which is surrounded by leaf-like ramifications.

Fossil record

Chaetocladus is known from upper Silurian konservat l\agerstätte, and found in association with other algae, arthropods, and annelid worms.^[2] Similar Dasycladean algae are reported from late-Ordovician lagerstatte.^[3]

Classification

Due to its morphological similarity to the extant order Dasycladales, Chaetocladus is considered to be an early cousin of this order. Unlike the majority of Dasycladales, Chaetocladus does not form deposit calcite - therefore it required much rarer taphonomic conditions to be preserved.^[4] Some genera now recognised as Chaetocladus were originally described as Graptolites.^[5]

References

1. LoDuca, S.T.; Kluessendorf, J.; Mikulic, D.G. (2003). "A New Noncalcified Dasycladalean Alga From The Silurian Of Wisconsin". Journal of Paleontology. 77 (6): 1152–1158. doi:10.1666/0022-3360(2003)077<1152:ANNDAF>2.0.CO;2.
2. LoDuca, S.T. (1997). "The Green Alga Chaetocladus (Dasycladales)". Journal of Paleontology. 71 (5): 940–949. JSTOR 1306570.
3. Young, G.A.; Rudkin, D.M.; Dobrzanski, E.P.; Robson, S.P.; Nowlan, G.S. (2007). "Exceptionally preserved Late Ordovician biotas from Manitoba, Canada". Geology. 35 (10): 883–886. doi:10.1130/G23947A.1.
4. Kenrick, P.; Vinther, J. (2006). "Chaetocladus gracilis n. sp., a non-calcified Dasycladales from the Upper Silurian of Skåne, Sweden". Review of Palaeobotany and Palynology. 142 (3–4): 153–160. doi:10.1016/j.revpalbo.2006.03.023. Retrieved 2007-10-10.
5. e.g. LoDuca, S.T. (1990). "Medusaegraptus mirabilis Ruedemann as a Noncalcified Dasyclad Alga". Journal of Paleontology. 64 (3): 469–474. JSTOR 1305597.