''Chamaesipho grebneffi'' is the first extinct member of the
Notochthamalinae to be described, and the oldest chthamaloid
barnacle
A barnacle is a type of arthropod constituting the subclass Cirripedia in the subphylum Crustacea, and is hence related to crabs and lobsters. Barnacles are exclusively marine, and tend to live in shallow and tidal waters, typically in eros ...
known. This species is a fully derived ''
Chamaesipho
''Chamaesipho'' is a genus of four-plated notochthamaline barnacles in the Pacific Ocean limited to Australian/New Zealand temperate waters. They are intertidal in preference, and tend to form crowded columnar colonies. They can be identified i ...
'', and indicates a considerable antiquity for
Chthamaloidea
The Chthamaloidea are a subdivision of Balanomorpha proposed by Newman and Ross to include barnacles with shell wall composed of rostrum, carina, and one to three pairs of latera, rarely supplemented with one or more whorls of basal imbricating ...
.
Three extinct species of ''
Chthamalus'' from the middle
Miocene
The Miocene ( ) is the first 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 means "less recen ...
of the faluns of Touraine, France were described in 2008 by Carriol.
the New Zealand species is
Oligocene
The Oligocene ( ) is a geologic epoch of the Paleogene Period and extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that define the epoch are well identified but the ...
, and considerably older.
Discussion
Like the three living species of ''
Chamaesipho
''Chamaesipho'' is a genus of four-plated notochthamaline barnacles in the Pacific Ocean limited to Australian/New Zealand temperate waters. They are intertidal in preference, and tend to form crowded columnar colonies. They can be identified i ...
'', the shell of ''C. grebneffi'' begins with 6 plates, fusing completely at about 2 mm diameter. Freegrown specimens show a stellate basal outline. The scutum is highly distinctive in tergal margin equal in length to basal margin. In all other ''Chamaesipho'', tergal margin is much shorter than basal.
[ The tergum is not definitely identified.
''Chamaesipho grebneffi'' is interpreted, from wear patterns on the shell, to have occupied high ]littoral
The littoral zone or nearshore is the part of a sea, lake, or river that is close to the shore. In coastal ecology, the littoral zone includes the intertidal zone extending from the high water mark (which is rarely inundated), to coastal areas ...
positions on shore. Entire assemblage described by Buckeridge indicates shallow agitated waters of several habitat zones.[
]
Nomenclature
* ''Chamaesipho brunnea'' . Buckeridge, 1983b: 80
References
External links
{{Taxonbar, from=Q16960984
Barnacles