''Tawera spissa'', the morning star shell, is a species of marine
bivalve
Bivalvia (), in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of marine and freshwater molluscs that have laterally compressed bodies enclosed by a shell consisting of two hinged parts. As a group, bival ...
from the
Veneridae family.
[MolluscaBase (2019). MolluscaBase. Tawera spissa (Deshayes, 1835). Accessed through: World Register of Marine Species at: http://www.marinespecies.org/aphia.php?p=taxdetails&id=507911 on 2019-06-24] ''T. spissa'' is
endemic
Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...
to
New Zealand
New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...
.
Description
''Tawera spissa'' is 20-25 mm in length and has a triangular shape with oblong
valves. Each valve has rows of ridges. The valves are often white with a variety of brown patterning, but can also be completely white or completely brown in colour. On the internal surface, the valves are white, with brown
adductor scars.
Habitat
Individuals occupy fine to coarse sand and light gravel substrates just below the surface. Their depth range is typically slightly below the low tide mark down to 200m in depth. They tend to be found in areas where there is some water movement. ''Tawera spissa'' may be the dominant species in subtidal benthic zones alongside ''
Purpurocardia purpurata'' in widespread open coastal communities or with ''
Zemysina globus'' in more sheltered conditions such as bays in southern New Zealand.
References
{{Taxonbar, from=Q3802399
Bivalves of New Zealand
Veneridae
Bivalves described in 1835