Br@chNet
Dallinella

Sous-embranchement (subphylum) des Rhynchonelliformea
Classe des Rhynchonellata
Ordre des Terebratulida
Sous-Ordre des Terebratellidina
Super-famille des Laqueoidea

 
 
 
 
 


Genus Dallinella Thomson, 1915
[Type species= Terebratella occidentalis var. obsoleta Dall, 1891, p. 186; = Terebratalia obsoleta Beecher, 1895, p. 382, 392 ]

Medium to large, biconvex, subquadrate to transversely oval, multiplicate with wide, subdued, median uniplication; beak erect, attrite, foramen large, mesothyrid to permesothyrid; deltidial plates conjunct in adults. Pedicle collar short, hinge teeth strong, dental plates ventrally recessive with very reduced, lateral umbonal cavities. Cardinalia as in Terebratalia, crural processes attenuated, anteriorly projecting. Loop trabecular.

Lower Miocene - Present

Diagnosis from volume 5 of the
Treatise on Invertebrate Paleontology (2006)

Extant Species of Dallinella
  • D. obsoleta (Dall, 1891)
  • Diagnosis


    Dallinella obsoleta   Dall, 1891

    Type locality: "dredged by the U. S. Steamer Albatross, in 113 fathoms, at Station 2984, off Cerros Island, Lower California"
    Depth range: 80 - 207 m.

    ? Dallinella occidentalis (Dall, 1871): see below...

    Diagnosis - original from Dall (1891)

    Shell more rounded than the original type with the sharp radiating ribs and sulci obsolete and represented chietiy by the brilliant scarlet lines of color which in the type surmount the ribs.
    Color: reddish (Dall, 1891; Helmcke, 1939).

     


    In Wells et al. (1983) "it is suggested that populations of deep water brachiopods such as Terebratulia transversa, Dallinella obsoleta and Terebratulina unguicula may be threatened off southern California by pollution and by accidental killing in other dredging opérations."

    Beecher (1895) wrote "the material for this work has kindly been furnished by Dr. William Dall of Washington. The specimens were dredged by the U. S. Steamer Albatross, in 113 fathoms, at Station 2984, off Cerros Island, Lower California. In a report on some shells from this expedition, by Dr. Dall, this brachiopod was described as Terebratella occidentalis var. obsoleta. Subsequent study, however, has led him to consider it as a distinct species under T. obsoleta (Plate II, figures 6-9), and this determination is here adopted." adding "In the previous paper it was stated that Terebratalia obsoleta was morphically equivalent to Terebratella dorsata,..."

    Thomson (1915) stated "this was the more unfortunate, as the actual species on which he established a different ontogenetic series from that of Terebratella, s.str., was Terebratella obsoleta, Dall, which is a dorsally uniplicate form." Thus he created a new genus Dallinella, with, Terebratella obsoleta, Dall, as type species. And, he pointed out : "I further desire to define the genotype as the species actually figured by Beecher under the name of T. obsoleta, Dall."


    Terebratalia or Dallinella occidentalis (Dall, 1871)

    This species has never been clearly described in Dall's publications nor by other authors to allow a comparison based on taxonomic characters. Consequently, or this species belongs to another genus or it is synonymous with D. obsoleta because both seems to occur in the same environment that is only possible for two species of the same genus with strong biological differences.


    Fossil species:
    • Terebratella occidentalis  Dall: Lower Miocene to Pleistocene
    • Dallinella smithi  (Arnold, 1903): Lower Pliocene - type-locality: Deadman Is., California - also Hatai (1940) in Takamori, Mutu province.
    • ? Terebratalia smithi brevis Hayasaka: Miocene to Pliocene, Japan

    Neogene species must always be compared to their living "relatives" (not the contrary) that generally leads to a same species - consequently biological species have no relationships to stratigraphy, just to biology even they are fossils!