The Calodiscidae Kobayashi, 1943 [nom. transl. Öpik, 1975 ex Calodiscinae Kobayashi, 1943] are a family of trilobites belonging to the order Agnostida that lived during the Lower Cambrian (Botomian and Toyonian). They are small or very small, and have a thorax of two or three segments. The Calodiscidae includes five genera (see box).
The probable ancestors of the Calodiscidae are among the Tsunydiscidae. The Calodiscidae had no descendants.[3]
Descriptionedit
Like all Agnostida, the Calodiscidae are diminutive and the headshield (or cephalon) and tailshield (or pygidium) are of approximately the same size (or isopygous) and outline. The central raised area of the cephalon (or glabella) has parallel sides or tapers forward, the front being rounded and expanded, and may be divided by transverse glabellar furrows. The occipital ring is defined by a complete transverse furrow and is neither spinose nor expanded. When present, the eye lobes are short and prominent. The thorax is only known in Chelediscus (two segments) and Sinodiscus (three segments). The pygidium has a wide, tapering axis of less than six segments.[2]
Referencesedit
^KOBAYASHI, T. 1943. Brief notes on the eodiscids 1, their classification with a description of a new species and a new variety. Proceedings of the Imperial Academy, Tokyo, 19, 37 - 42.
^ abWHITTINGTON, H. B. (1997). Volume 1 – Trilobita – Introduction, Order Agnostida, Order Redlichiida. Treatise on Invertebrate Paleontology. Vol. Part O, Revised. pp. 390–392.
^JELL, P. A. (1975). "Australian Middle Cambrian Eodiscoids with a review of the superfamily". Palaeontographica Abteilung A. 150: 1–97. cited in WHITTINGTON, H. B. (1997). Volume 1 – Trilobita – Introduction, Order Agnostida, Order Redlichiida. Treatise on Invertebrate Paleontology. Vol. Part O, Revised. pp. 348–349.
This Agnostida-related article is a stub. You can help Wikipedia by expanding it.
calodiscidae, kobayashi, 1943, transl, öpik, 1975, calodiscinae, kobayashi, 1943, family, trilobites, belonging, order, agnostida, that, lived, during, lower, cambrian, botomian, toyonian, they, small, very, small, have, thorax, three, segments, includes, five. The Calodiscidae Kobayashi 1943 nom transl Opik 1975 ex Calodiscinae Kobayashi 1943 are a family of trilobites belonging to the order Agnostida that lived during the Lower Cambrian Botomian and Toyonian They are small or very small and have a thorax of two or three segments The Calodiscidae includes five genera see box CalodiscidaeTemporal range Lower Cambrian PreꞒ Ꞓ O S D C P T J K Pg N Scientific classification Kingdom Animalia Phylum Arthropoda Class Trilobita Order Agnostida Suborder Eodiscina Superfamily Eodiscoidea Family CalodiscidaeKobayashi 1943 1 genera Calodiscus Korobovia Neocobboldia Pseudocobboldia Sinodiscus 2 Synonyms Brevidiscinae NeocobboldinaeTaxonomy editThe probable ancestors of the Calodiscidae are among the Tsunydiscidae The Calodiscidae had no descendants 3 Description editLike all Agnostida the Calodiscidae are diminutive and the headshield or cephalon and tailshield or pygidium are of approximately the same size or isopygous and outline The central raised area of the cephalon or glabella has parallel sides or tapers forward the front being rounded and expanded and may be divided by transverse glabellar furrows The occipital ring is defined by a complete transverse furrow and is neither spinose nor expanded When present the eye lobes are short and prominent The thorax is only known in Chelediscus two segments and Sinodiscus three segments The pygidium has a wide tapering axis of less than six segments 2 References edit KOBAYASHI T 1943 Brief notes on the eodiscids 1 their classification with a description of a new species and a new variety Proceedings of the Imperial Academy Tokyo 19 37 42 a b WHITTINGTON H B 1997 Volume 1 Trilobita Introduction Order Agnostida Order Redlichiida Treatise on Invertebrate Paleontology Vol Part O Revised pp 390 392 JELL P A 1975 Australian Middle Cambrian Eodiscoids with a review of the superfamily Palaeontographica Abteilung A 150 1 97 cited in WHITTINGTON H B 1997 Volume 1 Trilobita Introduction Order Agnostida Order Redlichiida Treatise on Invertebrate Paleontology Vol Part O Revised pp 348 349 nbsp This Agnostida related article is a stub You can help Wikipedia by expanding it vte Retrieved from https en wikipedia org w index php title Calodiscidae amp oldid 1124749257, wikipedia, wiki, book, books, library,
