Wood Bay Formation

Not to be confused with Wood Canyon Formation.

Wood Bay Formation
Stratigraphic range: Early Pragian–Late Emsian ~410.8–393.47  Ma PreꞒ Ꞓ O S D C P T J K Pg N
Type	Formation
Unit of	Andrée Land Group
Sub-units	See text
Underlies	Grey Hoek Formation
Overlies	Ben Nevis Formation
Thickness	3,000 metres (9,800 ft)
Location
Region	Spitsbergen, Svalbard
Country	Norway

The Wood Bay Formation is a geologic formation found on the island of Spitsbergen, Svalbard in Norway. It preserves fossils dating back to the Pragian and Emsian stages of the Devonian period. ^[1]

Stratigraphy

The Wood Bay Formation is divided into two main areas: the Woodfjorden area in the north and the Dicksonfjorden–Austfjorden area in the south. In the Woodfjorden area, the formation is further split into the Sigurdfjellet, Kapp Kjeldsen, Keltiefjellet, and Stjørdalen divisions, which are distinguished by the types of fish fossils found there. The Dicksonfjorden–Austfjorden area is divided into the Austfjorden, Dicksonfjorden, and Verdalen members based on differences in sedimentary features. These differing methods of classifying the formation's sub-units have led to difficulty in determining how one area corresponds to the other. ^[1]

Paleoenvironment

The Wood Bay Formation was likely coastal and may represent an estuarine or fjord-like environment. The presence of a Lingula fossil recovered from the formation might suggest some degree of marine influence. ^[1]

Fossil content

Acanthodians

Acanthodians are a group of stem–chondrichthyans found in Paleozoic deposits around the world. They are commonly represented in the fossil record by their spines and scales. The Acanthodian fauna of the Wood Bay Formation is not as well understood as the other animal groups present, but Xylacanthus grandis, the largest known acanthodian, is exclusively found here. ^[2]

Acanthodians
Genus	Species	Division	Notes	Images
"Gomphonchus"	"G." sp. [3]	Sigurdfjellet Division	An ischnacanthid.
"Nostolepis"	"N." sp. [3]		A climatiid.
Striacanthus	S. overathensis [2] [4]	Sigurdfjellet Division Kapp Kjeldsen Division	A diplacanthiform of uncertain placement. Originally described as the form genus "Onchus" overathensis.
Acanthodes?	A. sp.? [5]	Kapp Kjeldsen Division	An acanthodid. Only known within the Wood Bay Formation from scale fossils.
Cheiracanthus?	C. sp.? [5]		A cheiracanthid. Only known within the Wood Bay Formation from scale fossils.
Ptychodictyon?	P. sp.? [5]		A diplacanthiform. Only known within the Wood Bay Formation from scale fossils.
Xylacanthus	X. grandis [2]		An ischnacanthid.
	X. minutus [6]	Keltiefjellet Division
Mesacanthus	M. grandis [6]		A mesacanthid.

Agnathans

Agnathans are by far the most species–rich and well–known animal group present in the Wood Bay Formation. Osteostracans alone account for over one third of the total genera present in the formation. ^[7] All Agnathans known from the formation are considered "Ostracoderms", an informal grouping of armored jawless fish from the Paleozoic.

Heterostracans

Heterostracans
Genus	Species	Division	Notes	Images
Woodfjordaspis	W. felixi [8]	Sigurdfjellet Division	A pteraspidid.
Xylaspis	X. prima [9]		A protopteraspidid. Previously named Spitsbergaspis prima. [10]
Doryaspis	D. arctica [1] [11]	Sigurdfjellet Division Kapp Kjeldsen Division	A protopteraspidid. D. lyktensis and D. minor were previously assigned to Grummantaspis lyktensis and Ennosveaspis minor respectively. [11]
	D. groenhorgensis [1] [11]	Kapp Kjeldsen Division
	D. lyktensis [1] [11]
	D. nathorsti [1] [11]	Kapp Kjeldsen Division Keltiefjellet Division
	D. minor [1] [11]	Stjørdalen Division
Gigantaspis	G. minima [12]	Sigurdfjellet Division	A pteraspidid. G. laticephala was previously assigned to Zascinaspis laticephala. [12] [13]
	G. isachseni [12]	Kapp Kjeldsen Division
	G. laticephala [12]
	G. bocki [12]

Osteostracans

Osteostracans
Genus	Species	Division	Notes	Images
Benneviaspis	B. grandis [14]	Sigurdfjellet Division	A benneviaspidid. B. loevgreeni was changed from B. lövgreeni, as diacritics are not allowed in scientific names according to the International Code of Zoological Nomenclature. [15]
	B. loevgreeni [14]
	B. maxima [14]
Norselaspis	N. glacialis [16]		A kiaeraspidid.
Belonaspis	B. puella [14]		A boreaspidid.
Machairaspis	M. isachseni [14]		A zenaspidid.
	M. battaili [14]	Kapp Kjeldsen Division
Cephalaspis	"C." curta [1] [17]	Sigurdfjellet Division	A cephalaspid. Previously considered a wastebasket taxon. Many species previously assigned to Cephalaspis have been reassigned to different genera or are considered dubious.
	"C." sp. [7]	Sigurdfjellet Division Kapp Kjeldsen Division
Boreaspis	"B." ceratops [1] [18] [19]	Sigurdfjellet Division	A boreaspidid.
	"B." ginsburgi [1] [18] [19]
	"B." batoides [18] [19]	Kapp Kjeldsen Division
	B. puella [18]
	B. triangularis [18]
	"B." intermedia [1] [18] [19]	Sigurdfjellet Division Kapp Kjeldsen Division
	B. macrorhynchus [14] [18]
	B. rostrata [1] [14]
	B. spinicornis [18]	Kapp Kjeldsen Division Keltiefjellet Division
Spatulaspis	S. robusta [18] [14]		A boreaspidid. Previously assigned to Boreaspis.
	S. costata [18] [14]
Axinaspis	A. whitei [18]	Kapp Kjeldsen Division	A kiaeraspidid.
Acrotomaspis	A. instabilis [16] [18]
Dicranaspis	D. circinus [18] [14]		A boreaspidid.
	D. curtirostris [18] [14]	Kapp Kjeldsen Division Keltiefjellet Division
	D. gracilis [18] [14]
Hildenaspis	H. digitalis [20]	Keltiefjellet Division	A cephalaspidid.
Gustavaspis	G. trinodus [16] [18]	Keltiefjellet Division Stjørdalen Division	Previously assigned to Acrotomaspis trinodus.
Diademaspis	D. poplinae [7] [14]	Sigurdfjellet Division Kapp Kjeldsen Division Keltiefjellet Division Stjørdalen Division	A zenaspidid.
Parameteoraspis	P. oblonga [14]	Sigurdfjellet Division Kapp Kjeldsen Division	A parameteoraspidid. previously assigned to Cephalaspis and previously named Meteoraspis. [7] P. hoegi and P. borealis are considered nomina dubia. There are an additional four undescribed species, at least three of which belong to the Kapp Kjeldsen Division. [14]
	P. caroli [14]	Kapp Kjeldsen Division
	P. oberon [14]
	P. lata [14]
	P. gigas [14]	Keltiefjellet Division
	P. hoegi [14]
	P. lanternaria [14]
	P. menoides [14]
	P. moythomasia [14]	Stjørdalen Division
	P. semicircularis [14]
	P. laticornis [14]	Unknown, probably Kapp Kjeldsen Division
	P. borealis [14]	Unknown
Nectaspis	N. peltata [1] [14]	Kapp Kjeldsen Division	A cephalaspidid.
	N. areolata [1] [14]	Kapp Kjeldsen Division Keltiefjellet Division Stjørdalen Division
	N. dellei [14]	Stjørdalen Division

Thelodonts

Thelodonts
Genus	Species	Division	Notes	Images
Turinia	T. pagei [21] [7]	Sigurdfjellet Division	A coelolepid.
Sigurdia	S. lata [22]
Amaltheolepis	A. sp. [7]	Sigurdfjellet Division Keltiefjellet Division	A turiniid.
	A. winsnesi [23]	Stjørdalen Division

Osteichthyans

Osteichthyans, or bony fish, are primarily represented by sarcopterygians in the Wood Bay Formation. Osteichthyans in general are poorly represented at the formation compared to other animal groups.

Osteichthyans
Genus	Species	Division	Notes	Images
Powichthys	P. spitsbergensis [24]	Sigurdfjellet Division	A powichthyid.
Porolepis	P. sp. [7]		A porolepidid. P. elongata and P. brevis may be junior synonyms of P. spitsbergensis. [25]
	P. elongata [7]	Kapp Kjeldsen Division
	P. brevis [7]	Keltiefjellet Division
	P. spitsbergensis [7]	Unknown
Janvierpaucidentes	J. tuulingi [26]	Dicksonfjorden Member (= Keltiefjellet Division) [1]	A dipnoan.
Heimenia	H. ensis [23]	Stjørdalen Division	A porolepidid.
Orvikuina	O. sp. [27]		A palaeoniscoid.

Placoderms

Placoderms are a group of armored fish that lived during the Late Silurian and Devonian periods of the Paleozoic. They represent the second most well–known group of animals from the Wood Bay Forrmation.

Placoderms
Genus	Species	Division	Notes	Images
Sigaspis	S. lepidophora [28]	Sigurdfjellet Division	An actinolepid or actinolepidoid arthrodire placoderm. [29]
Arctaspis	A. sp. indet. [7]		A phlyctaeniid.
	A. holtedahli [30]	Kapp Kjeldsen Division
	A. kiaeri [7]
	A. maxima [7]	Keltiefjellet Division
Dicksonosteus	D. arcticus [7]	Kapp Kjeldsen Division	A phlyctaeniid.
Heintzosteus	H. brevis [7]		An arctolepid. Previously assigned to Jaekelaspis brevis.
Lehmanosteus	L. hyperboreus [7] [6]		A basal arthrodire.
Elegantaspis	E. reticornis [7] [30]	Unknown, potentially the Kapp Kjeldsen Division	A phlyctaeniid.
Lataspis	L. brevicornis [31]	Unspecified, at least one species found in the Kapp Kjeldsen Division	Previously named Plataspis. [31] [32] [30]
	L. rotundicornis [31]
Arctolepis	A. decipens [7]	Keltiefjellet Division	A phlyctaeniid.
Actinolepis	A. sp. [7] [23]	Stjørdalen Division	An actinolepid.
Herasmius	H. granulatus [23]		A heterosteid.
Heterogaspis	H. gigantea [7]		A phlyctaeniid.
Homosteus	H. arcticus [7] [23]		A homostiid. Also referred to as Homostius.

Invertebrates

Invertebrate fossils from the Wood Bay Formation are scarce and are mostly represented by microfossils.

Invertebrates
Genus	Species	Division	Notes	Images
"Spirorbis"	"S." sp. [5]	Kapp Kjeldsen Division	An extant genus of tube-forming annelid worm that was once assigned to many fossil specimens. A 2009 study determined that all instances of the genus from before the Jurassic period likely represent microconchid molluscs instead. This would include the specimens from the Wood Bay Formation. [33] [34]
Pterygotus?	P. sp.? [12] [13]		Fragments of a large eurypterid that are assigned to Pterygotus. Occurs alongside Gigantaspis laticephala. [12]
Lingula	L. sp [35]	"Uppermost Wood Bay Formation"	A modern brachiopod with a fossil record potentially extending to the Cambrian period. Only represented in the Wood Bay Formation by one specimen. [35]
Isochilina	I. isochilinoides [36]	Unspecified	An ostracod crustacean.
Holtedahlia	H. teres [36]		An ostracod crustacean.

Plants

Plants
Genus	Species	Division	Notes	Images
Trochiliscus?	T. sp.? [5]	Kapp Kjeldsen Division	A charophyte algae.
"Hostinella"	"H." sp. [5] [11]		A form genus that represents the branching stems of a plant. Previously named Hostimella.

Ichnotaxa

Ichnotaxa
Genus	Species	Division	Notes
Cruziana	C. polaris [35] [37]	Kapp Kjeldsen Division Keltiefjellet Division	Traces of a trilobite or trilobite-like arthropod.
PIanolites	P. isp. [37]	Keltiefjellet Division
Merostomichnites	M. isp. [37]		The trackways of an arthropod, potentially a eurypterid.
Rusophycus	R. isp. [37]		Arthropod resting traces.
Lockeia	L. isp. [37]
Isopodichnus	I. isp. [37]	Keltiefjellet Division Stjørdalen Division	The resting or feeding traces of an arthropod. Similar in appearance to Cruziana.
Taenidium	T. isp. [37]
Skolithos	S. helicoidalis [38]	Verdalen Member (= Stjørdalen Division)	A vertical, helical tube interpreted as the trace of a plant rhizolith or animal burrow.
Undichna	U. septemsulcata [39]	"Middle Wood Bay Formation"	A swimming trace of an acanthodian, possibly Diplacanthus. One of the oldest vertebrate trace fossils known.
Svalbardichnus	S. trilobus [35]	"Upper Wood Bay Formation"	Feeding traces of a supposedly Nahecaris -like phyllocardid crustacean.
Beaconites	B. baretti [35] [37] [40]	Unspecified	Found predominantly in sandstone beds with wave marks.
Siskemia	S. cf. elegans [35]	Unspecified	Interpreted as the trackways of an arthropod pushing itself through the sediment.

See also

• Earth sciences portal
• Norway portal
• Paleontology portal

• List of fossiliferous stratigraphic units in Norway
• Old Red Sandstone

References

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