''Megasurcula howei'' is an extinct
species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...
of
sea snail, a marine
gastropod mollusk
Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is e ...
in the
family
Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...
Pseudomelatomidae
Pseudomelatomidae is a family of predatory sea snails, marine gastropods included in the superfamily Conoidea (previously Conacea) and part of the Neogastropoda ( Bouchet & Rocroi, 2005).
In 1995 Kantor elevated the subfamily Pseudomelatomina ...
, the turrids and allies.
Description
The length of the shell attains 36 mm, its diameter 23.6 mm.
This high-spired, biconic species differs from ''
Megasurcula condonana''
(Anderson and Martin, 1914) by having a smoothly conic
spire
A spire is a tall, slender, pointed structure on top of a roof of a building or tower, especially at the summit of church steeples. A spire may have a square, circular, or polygonal plan, with a roughly conical or pyramidal shape. Spires a ...
and relatively narrower
body whorl. When the body whorl angulation is used as a point of reference, in non-apertural view, the upper cone of ''M. howei'' is relatively higher than the lower cone, whereas the reverse is true in specimens of the stout-shelled ''M. condonana''. Further differences are the more acute sutural angle and the concave profile of ''M. condonana''.
It is closely related to † ''
Megasurcula guayasensis'' of the Miocene in
Ecuador
Ecuador ( ; ; Quechua: ''Ikwayur''; Shuar: ''Ecuador'' or ''Ekuatur''), officially the Republic of Ecuador ( es, República del Ecuador, which literally translates as "Republic of the Equator"; Quechua: ''Ikwadur Ripuwlika''; Shuar: ' ...
, but differs by being less slender, a bit taller and less finely noded.
Miocene Gastropods and Biostratigraphy of the Kern River Area, California; United States Geological Survey Professional Paper 642 : Megasurcula howei
Distribution
Fossils of this marine species have been found in Miocene
The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...
strata of the Temblor Formation
The Temblor Formation is a geologic formation in California. It preserves fossils dating back from the Late Oligocene to the Middle Miocene of the Neogene period. It is notable for the famous Sharktooth Hill deposit (otherwise known as Ernst Q ...
, California.
References
* Hanna and Hertlein, 1938, Journal of Paleontology v. 12 no. 1 p. 107
External links
California Academy of Sciences: ''Megasurcula howei''
{{DEFAULTSORT:Megasurcula Howei
howei
Gastropods described in 1938