monotypic genus
In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispec ...
of
brachiopods
Brachiopods (), phylum Brachiopoda, are a phylum of trochozoan animals that have hard "valves" (shells) on the upper and lower surfaces, unlike the left and right arrangement in bivalve molluscs. Brachiopod valves are hinged at the rear end, whi ...
belonging to the family
Dallinidae
Dallinidae is a family of brachiopods belonging to the order Terebratulida.
Genera
Genera:
* †'' Antigoniarcula'' Elliott, 1959
* '' Campages'' Hedley, 1905
* ''Dallina
''Dallina'' is a genus of small to average size lampshells (maximum ...
. The only species is ''Jaffaia jaffaensis'' from southern Australia.
Description
''J. jaffaensis'' reaches a maximum length of 23.4 mm and fits the following diagnosis:
Overall outline ovoid to circular, relatively thin laterally and with commissures (junction between the dorsal and ventral shells/valves) straight, anterior commissure rectimarginate to lightly sulcate. Beak (posterior point of shell) suberect, with deltidial plates conjunct (as symphytium) and mostly exposed, and bearing a small foramen. Hinge teeth large relative to symphytium, with swollen bases (not supported by 'dental plates'). Cardinalia with inner and outer hinge plates separated by thick crural bases, inner hinge plates forming a V-shaped septalium supported by median septum. Cardinal process well developed, supported anteriorly by a triangular ridge between the hinge plates, and with a posteriorly facing myophore. The median septum does not reach mid-valve, highest at junction with lateral connecting bands of brachial loop. Crura are short, subparallel, and with short and pointed crural processes. Adult brachial loop 'trabecular', supporting a 'plectolophous'
lophophore
The lophophore () is a characteristic feeding organ possessed by four major groups of animals: the Brachiopoda, Bryozoa, Hyolitha, and Phoronida, which collectively constitute the protostome group Lophophorata.)
The genus is very similar in morphology to the genus '' Nipponithyris'' (sharing a large anteriorly supported cardinal process, thick crural bases, 'trabecular' brachial loop, large and thick based hinge teeth, and rounded shell outline without strong folding) and they may prove
synonymous
A synonym is a word, morpheme, or phrase that means exactly or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are all ...
.
Distribution
''Jaffaia jaffaensis'' is recorded from the continental shelf and continental slope around southern, eastern, and western Australia with a bathymetric range of 67 to 550 m depth.