middle Devonian

{{Infobox geologic timespan

| name = Middle Devonian

| color = Middle devonian

| top_bar =

| time_start = 393.3

| time_start_prefix =

| time_start_uncertainty = 1.2

| time_end = 382.7

| time_end_prefix =

| time_end_uncertainty = 1.6

| image_map = Mollweide Paleographic Map of Earth, 390 Ma (Eifelian Age).png

| caption_map = A map of Earth as it appeared 390 million years ago during the Middle Devonian Epoch, Eifelian Age

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| timeline = Devonian

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| name_formality = Formal

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| celestial_body = Earth

| usage = Global (ICS)

| timescales_used = ICS Time Scale

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| chrono_unit = epoch

| strat_unit = series

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| timespan_formality = Formal

| lower_boundary_def = Fad of the Conodont Polygnathus costatus partitus

| lower_def_candidates =

| lower_gssp_candidates =

| lower_gssp_location = Wetteldorf Richtschnitt, Eifel hills, Germany

| lower_gssp_coords ={{Coord|50.1496|N|6.4716|E|display=inline}}

| lower_gssp_accept_date = 1985

| upper_boundary_def = FAD of the Conodont Ancyrodella rotundibola

| upper_def_candidates =

| upper_gssp_candidates =

| upper_gssp_location = Col du Puech de la Suque, Montagne Noire, France

| upper_gssp_coords = {{Coord|43.5032|N|3.0868|E|display=inline}}

| upper_gssp_accept_date = 1986

}}

In the geological timescale, the Middle Devonian epoch (from 393.3 ± 1.2 million years ago to 382.7 ± 1.6 million years ago) occurred during the Devonian period, after the end of the Emsian age.

The Middle Devonian epoch is subdivided into two stages: Eifelian and Givetian.

Life in the Middle Devonian

In the middle Devonian the armored jawless fish known as ostracoderms were declining in diversity and instead the jawed fish were thriving and increasing in diversity in both the oceans and freshwater. The shallow, warm, oxygen-depleted waters of Devonian inland lakes, surrounded by primitive plants, provided the environment necessary for certain early fish to develop essential characteristics such as well developed lungs, ability to crawl out of the water and onto the land for short periods of time, possibly in search of food which would be developed by the tetrapods later in the Late Devonian which are descendents of these early fish.

The earliest forest grew in the Middle Devonian (Eifelian) time. This new environment was formed by cladoxylopsid trees including Calamophyton.{{cite journal|author=Davies, Neil S., McMahon, William J. and Berry, Christopher M.|year=2024|url=https://orca.cardiff.ac.uk/id/eprint/166971/1/davies-et-al-2024-earth-s-earliest-forest-fossilized-trees-and-vegetation-induced-sedimentary-structures-from-the.pdf|title=Earth's earliest forest: fossilized trees and vegetation-induced sedimentary structures from the Middle Devonian (Eifelian) Hangman Sandstone Formation, Somerset and Devon, SW England|journal=Journal of the Geological Society|doi=10.1144/jgs2023-204|archive-url=https://web.archive.org/web/20240309154116/https://orca.cardiff.ac.uk/id/eprint/166971/1/davies-et-al-2024-earth-s-earliest-forest-fossilized-trees-and-vegetation-induced-sedimentary-structures-from-the.pdf|archive-date=9 March 2024|url-status=live}}

The Taghanic event took place near the end of the Middle Devonian.

References

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Category:Middle Devonian