Trilobite Order Redlichiida
Trilobites
 
Redlichiid Trilobites


Page within: Trilobite Classification
Also see: Trilobite Paleobiology 
 

Trilobite Taxonomy
Trilobite Phylogeny
Phylum Arthropoda
Subphylum Chelicerata
or Subphylum Schizoramia *
Superclass Arachnomorpha *
Class Trilobita

    Order Agnostida
    Order Redlichiida
    Order Corynexochida
    Order Phacopida
    Order Lichida
    Order Proetida
    Order Harpetida
    Order Ptychopariida
    Order Asaphida
    Order Odontopleurida
    Order Nectaspida
Trilobite Relatives
o Arthropoda
`--o Trilobita
   |?-Agnostida
   |?-Eodiscina
   `--+--o Redlichiida
      |  |--Olenellina
      |  `--Redlichiina
      |--Corynexochida
      |--Phacopida
      |--Lichida
      |--Odontopleurida
      `--o Librostoma
         |--Proetida
         |--Harpetida
         |--Ptychopariida
         `--Asaphida
* Different taxonomies are found, most recently with trilobites contained in Superclass Arachnomorpha in Subphylum Schizoramia.

Members of trilobite Order Redlichiida (pronouced Red-li-chee-da) are the oldest trilobites known from the fossil record. The Redlichiids appear in the Cambrian Epoch 2 and disappear from the fossil record prior to the Furongian at the end of the Cambrian. The order is believed to contain the progenitors of members of Order Corynexochida, and Order Ptychopariida.

A number of morphological features in the Redlichiids are considered to be the characteristics of the earlier and more primitive trilobites. These include: 1) numerous thoracic segments having spinose tips; 2) large and semicircular cephalon; 3) large crescent-shaped eyes; 4) and a diminutive (micropygous) pygidium having one to a few segments.

Order Redlichiida is divided into two suborders, Olenellina and Redlichiina. Of the two, the Olenellina are considered to be the earliest trilobites. Primarily due to their lack of facial sutures, some scientists have argued unsuccessfully for their separation from Trilobita. In all likelihood, Olenellina is most closely related to the last arthropod common ancestor of the trilobites.

Lower Cambrian Earth, noting location of Laurentia and Gondwana  The Olenellids are restricted to what was Laurentia in the Lower Cambrian, which now includes part of North America. In contrast, the Redlichiina are found in numerous Lower Cambrian locations that were not part of Laurentia. The different stratigraphical ranges are important as they form the basis for the phylenogy of Redlichiida. In fact, Lieberman (2002) has argued that cladistic analysis together with the biogeographic data supports the notion that early trilobite cladogenesis (i.e., the evolutionary splitting) occurred about coincident with the breakup of Pannotia sometime between 600–550 million years ago. Lieberman also conducted cladistic analyses among a group of basal trilobites within the Redlichiina, and the paraphyletic Fallotaspidoids. The group had primitive characteristics, such as the absence of facial sutures allying them with the Olenellina, and other characteristics allying them with the Redlichiina. Shared characteristics supported a phylogenetic position of the fallotaspids as transitional to all or almost all other trilobites except the Olenellina.

The Olenellid Fallotaspis from Morocco at about 540 mya has been cited by Fortey (2000) as the oldest trilobite in the fossil record. This Fallotaspis possessed relatively large holochroal eyes. Redlichids are found in two of the world's famous Cambrian Lagerstätten, the Maotianshan Shales near Chengjiang in China, as well as Emu Bay in Southern Australia. They are also commonly found in many sites in the western part of the United States and Canada. Many examples from these and other various fossil sites are shown below.

The members of Family Olenellidae have been proposed as chemoautotrophic symbionts (Fortey, 2005). Their wide thoraces, large numbers of thoracic segments, remarkably thin exoskeletons and, in some species, degenerate hypostome, and the occasional development of brood pouches are all consistent with this hypothesis. The Olenids appear well adapted to anoxic. Their extended pleural areas could have provided area for the cultivation of sulfur bacteria. It is feasible that the bacteria were grown on the ventral membrane beneath the extended pleurae and/or on the appendages. Among living animals, the gills of bivalves or the appendages of carideans are modified in chemoautotrophic symbionts for bacterial growth.

 

Suborder Olenellina

Subphylum Chelicerata
Class Trilobita
Order Redlichiida

    Suborder Olenellina
          Superfamily Olenelloidea
                Family Olenellidae
                Family Holmiidae 
          Superfamily Fallotaspidoidea
                Family Archaeaspididae
                Family Fallotaspididae
                Family Judomiidae
                Family Neltneriidae
                Family Nevadiidae 
    Suborder Redlichiina
          Superfamily Emuelloidea
                Family Emuellidae
                Family Megapharanaspidae 
          Superfamily Redlichioidea
                Family Redlichiidae
                Family Redlichinidae
                Family Dolerolenidae
                Family Yinitidae
                Family Mayiellidae
                Family Gigantopygidae
                Family Saukiandidae
                Family Metadoxididae
                Family Redlichinidae
                Family Metadoxididae
                Family Kuechowiidae
                Family Menneraspididae
                Family Chengkouaspidae 
          Superfamily Paradoxidoidea
                Family Paradoxididae
                Family Centropleuridae
                Family Xystriduridae
Eofallotaspis
Peachella
Eofallotaspis sp.
Family Fallotaspidoidea
Lower Cambrian
Campito Formation, Esmeralda County, Nevada
Peachella brevasina
Family Olenellidae
Subfamily Biceratopsinae
Late, Lower Cambrian
Cararra Formation, Nopah Range, Inyo County, California
Olenellus
Olenellus chiefensis
Family Olenellidae
Lower Cambrian
Pioche Shale, Lincoln County, Nevada
Olenellus fowleri
Family Olenellidae
Lower Cambrian
Pioche Shale, Lincoln County, Nevada
Olenellus schucherti
Olenellus gilberti
Family Olenellidae Subfamily: Olenellinae
Lower Cambrian
Pioche Shale, Lincoln County, Nevada
Bristolia bristolensis
Family Olenellidae
Lower Cambrian
Pioche Shale, Nevada
Olenellus schucherti
Family Olenellidae
Lower Cambrian
Eager formation, British Columbia, Canada
Fallotaspis sp.
Superfamily Fallotaspidoidea
Family Fallotaspididae
Lower Cambrian
Zagora, Morocco
Wanneria sp.
Family Olenellidae
Subfamily Wanneriinae
Lower Cambrian
Eager formation, British Columbia, Canada
Fallotaspis sp.
Superfamily Fallotaspidoidea
Family Fallotaspididae
Lower Cambrian
Inyo-White Mountains, California
Olenellus sp
Suborder Olenellina
Superfamily Olenelloidea
Lower Cambrian
Eager formation, B.C., Canada
Esmeraldina (Palmettaspis)
Suborder Olenellina Superfamily Olenelloidea Family Holmiidae
Lower Cambrian
Esmeralda County, Nevada
Olenellus terminatus
Olenellus clarki
Suborder Olenellina Superfamily Olenelloidea Family Olenellidae
Lower Cambrian
Latham Shale, California
Bristolia mojavensis
Suborder Olenellina Superfamily Olenelloidea Family Olenellidae
Lower Cambrian
Latham Shale, California
Nevadia weeksi
Superfamily Fallotaspidoidea
Family Nevadiidae
Lower Cambrian
Poleta Formation
Nevada
Olenellus terminatus
Superfamily Olenelloidea
Family Olenellidae Subfamily Olenellinae
Lower Cambrian
Pioche Shale, Nevada
Teresellus goldfieldensis Trilobite
Olenellus fremonti
Family Olenellidae
Subfamily Olenellinae
Lower Cambrian
Pioche Sale, Nevada

Teresellus goldfieldensis
Family Olenellidae Subfamily: Olenellinae
Lower Cambrian
Poleta Formation, Nevada

Suborder Redlichiina

Wutingasps tingi
Family
Redlichiidae
early Middle Cambrian
Changjiang Maotianshan Shales, China
Redlichia takooensis
Family Redlichiidae
Lower Cambrian
Emu Bay Shale, Australia
Bathynotus keuichousensis
Family Chenkouaspidae
Lower Cambrian
Kaili formation,
Guizhou Province, China
Paradoxides
Xystridura saint-smithi
Superfamily Paradoxidoidea
Family Xystriduridae, Subfamily Xystridurinae
Middle Cambrian
Mount Isa, Australia
Bathynotus elongatus
Family Chenkouaspidae
Lower Cambrian
Kaili formation,
Guizhou Province, China
Acadoparadoxides
Superfamily Paradoxidoidea
Family Paradoxididae, Subfamily Paradoxidinae
Cambrian
Sahara Desert, Morocco
Bergeroniellus asiaticus
Family Redlichiidae
Lower Cambrian Botomian Stage
Sinsk Formation, Lena River, Russia
     
Redlichia (Pteroredlichia) chinensis
Family Redlichiidae
Middle Cambrian
Hunan Province, China