Rhynchonellida

Rhynchonellida; Temporal range: Upper Ordovician–Recent PreꞒ Ꞓ O S D C P T J K Pg N
	Rhynchotrema dentatum, a rhynchonellid brachiopod from the Cincinnatian (Upper Ordovician) of SE Indiana.
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Brachiopoda
Class:	Rhynchonellata
Order:	Rhynchonellida; Kuhn, 1949
Subgroups
	See text.

The

articulate brachiopods, the other being the order Terebratulida. They are recognized by their strongly ribbed wedge-shaped or nut-like shells, and the very short hinge

line.

The hinges come to a point, a superficial resemblance to many (

mollusk

shells. The loss of the hinge line was an important evolutionary innovation, rhynchonellids being the first truly non-strophic shells with a purely internal articulation (teeth-sockets).

Strong radiating ribs are common in this group; and there are generally very strong plications or accordion-like folds on the

delthyrium

may be partially closed.

Morphologically, the rhynchonellid has changed little since its appearance during the

terminal Paleozoic extinction, it experienced a revival during the Early Jurassic period, and became the most abundant of all brachiopods during the Mesozoic

Era.

Classification

This classification down to the level of

genera is based on Kazlev^[1] and Emig.^[2]

Extant subgroups

Superfamily Pugnacoidea
- Family Basiliolidae
  - Subfamily Acanthobasiliolinae
    - Acanthobasiliola
  - Subfamily Basiliolinae
    - Basiliola
    - Basiliolella
    - Eohemithiris
    - Rhytirhynchia
  - Subfamily Uncertain
    - Striarina
Superfamily Dimerelloidea
- Family Cryptoporidae
  - - Aulites
    - Cryptopora
Superfamily Norelloidea
- Family Frieleiidae
  - Subfamily Freileiinae
    - Frieleia
    - Compsothyris
    - Grammetaria
    - Sphenarina
  - Subfamily Hispanirhynchiinae
    - Abyssorhynchia
    - Hispanirhynchia
    - Manithyris
    - Parasphenarina
  - Subfamily Neorhynchiinae
    - Neorhynchia
- Family
  Tethyrhynchiidae
  - - Tethyrhynchia
Superfamily Hemithiridoidea
- Family Hemithyrididae
  - - Hemithiris
    - Pemphixina
- Family Notosariidae
  - - Notosaria

Extinct Subgroups

Superfamily Ancistrorhynchoidea
Superfamily Rhynchotrematoidea
Superfamily Uncinuloidea
Superfamily Camarotoechioidea
Superfamily Rhynchotetradoidea
Superfamily Lambdarinoidea
Superfamily Wellerelloidea
Superfamily Rhynchoporoidea
Superfamily Stenoscismatoidea

References

^ M. Alan Kazlev. "Order Rhynchonellida". Archived from the original on March 13, 2006. Retrieved March 10, 2006.
^ Christian C. Emig. "Systematics of extant brachiopod taxa" (PDF). Archived from the original (PDF) on May 13, 2006. Retrieved March 10, 2006.

External links

Phylum Brachiopoda

[Kazlev-1] M. Alan Kazlev. "Order Rhynchonellida". Archived from the original on March 13, 2006. Retrieved March 10, 2006.

[2] Christian C. Emig. "Systematics of extant brachiopod taxa" (PDF). Archived from the original (PDF) on May 13, 2006. Retrieved March 10, 2006.

[1]

[2]