Raphiophoridae is a family of small to average-sized trilobites that first occurred at the start of the Ordovician and became extinct at the end of the Middle Silurian.
All raphiophorids are blind, with headshields (or cephalons) that are triangular to subcircular, and many carry long, trailing genal spines, a forward-directed rapier-like spine on the central raised area (or glabella), or both, with the glabella often inflated and the natural fracture lines (or sutures) of the cephalon coinciding with its margin. The thorax typically has five to seven segments[1] (except for the genera Taklamakania, Pseudampyxina, Nanshanaspis, and Kongqiangheia, which have only 3). As mentioned before, all raphiophorids are blind. Many, if not most, genera have no eyes whatsoever, though a few, such as Lehnertia, have vestigial tubercles that correspond to the compound eyes of their ancestors.
Distributionedit
Raphiophoridae currently includes two officially recognized subfamilies. The nominal subfamily Raphiophorinae originated from the Upper Tremadocian and died out during the Lower Ludlow, and has 217 species assigned to it divided over 26 genera. The subfamily Endymioniinae occurred from the Floian or possibly from the Lower Tremadocian to the Upper Katian and contains 36 species in 13 genera. The time of the first occurrence depends on whether the inadequately known monotypic genus Typhlokorynetes from the Lower Tremadocian of Laurentia is considered an endymioniin. Raphiophorids are generally found in deep-water sediments, and have a cosmopolitan distribution from the Floian to the Ordovician–Silurian extinction events with diversity peaking from the Darriwilian to the Sandbian. Raphiophorus survived into the Silurian.[2]
Taxonomyedit
The subfamily Taklamakaniinae was erected to bring together the genera Nanshanaspis, Pseudampyxina, and Taklamakania, (and then, later, Kongqiangheia) on the basis that they all have only three thoracic segments. Analysis of adult anatomy of these genera and larval stages of other raphiophorids showed they most probably developed through paedomorphosis from three different ancestors, so provide an example of parallel evolution. Nanshanaspis closely resembles young Globampyx, Pseudampyxina strongly looks like juvenile Raymondella, and Taklamakania is almost identical to early stages of Ampyxina. Since the three genera of the Taklamakaniinae have been demonstrated to be unrelated to each other, this subfamily is regarded as polyphyletic, and has been synonymized with the Raphiophorinae.[3]
Generaedit
These genera are assigned to the Raphiophoridae:[1]
^ abFortey, R.A. (1975). The Ordovician Trilobites of Spitsbergen [II. Asaphidae, Nileidae, Raphiophoridae and Telephinidae of the Valhallfonna Formation]. Norsk Polarinstitutt Skrifter. Vol. 162. Oslo: Norsk Polarinstitutt.
^J.M. Adrian (2014). "20. A synopsis of Ordovician trilobite distribution and diversity". In D.A.T. Harper; T. Servais (eds.). Early Palaeozoic Biogeography and Palaeogeography. Memoirs of the Geological Society of London. Vol. 38. Geological Society of London. p. 490. ISBN978-1862393738.
^Zhou, Z.; Webby, B.D.; Yuan, W. (1995). "Ordovician trilobites from the Yingan Formation of northwestern Tarim, Xinjiang, northwestern China". Alcheringa: An Australasian Journal of Palaeontology. 19 (1): 47–72. Bibcode:1995Alch...19...47Z. doi:10.1080/03115519508619098.
January 01, 1970
raphiophoridae, confused, with, rhaphidophoridae, family, small, average, sized, trilobites, that, first, occurred, start, ordovician, became, extinct, middle, silurian, temporal, range, ordovician, middle, silurian, preꞒ, curled, ampyx, nasutus, showing, ceph. Not to be confused with Rhaphidophoridae Raphiophoridae is a family of small to average sized trilobites that first occurred at the start of the Ordovician and became extinct at the end of the Middle Silurian RaphiophoridaeTemporal range Ordovician to Middle Silurian PreꞒ Ꞓ O S D C P T J K Pg N Curled Ampyx nasutus showing the cephalon genal spines amp glabellar spine Scientific classification Domain Eukaryota Kingdom Animalia Phylum Arthropoda Class Trilobita Order Asaphida Superfamily Trinucleioidea Family RaphiophoridaeAngelin 1854 Subfamilies Raphiophorinae Angelin 1854 Endymioniinae Raymond 1920 see text for genera Synonyms Subfamilies Ampyxininae Ampyxinellinae Taklamakaniinae Typhlokorynetidae damghanampyx ghobadipour fossil from Lashkark Formation Ordovician Damghan Iran Contents 1 Anatomy 2 Distribution 3 Taxonomy 3 1 Genera 4 ReferencesAnatomy editAll raphiophorids are blind with headshields or cephalons that are triangular to subcircular and many carry long trailing genal spines a forward directed rapier like spine on the central raised area or glabella or both with the glabella often inflated and the natural fracture lines or sutures of the cephalon coinciding with its margin The thorax typically has five to seven segments 1 except for the genera Taklamakania Pseudampyxina Nanshanaspis and Kongqiangheia which have only 3 As mentioned before all raphiophorids are blind Many if not most genera have no eyes whatsoever though a few such as Lehnertia have vestigial tubercles that correspond to the compound eyes of their ancestors Distribution editRaphiophoridae currently includes two officially recognized subfamilies The nominal subfamily Raphiophorinae originated from the Upper Tremadocian and died out during the Lower Ludlow and has 217 species assigned to it divided over 26 genera The subfamily Endymioniinae occurred from the Floian or possibly from the Lower Tremadocian to the Upper Katian and contains 36 species in 13 genera The time of the first occurrence depends on whether the inadequately known monotypic genus Typhlokorynetes from the Lower Tremadocian of Laurentia is considered an endymioniin Raphiophorids are generally found in deep water sediments and have a cosmopolitan distribution from the Floian to the Ordovician Silurian extinction events with diversity peaking from the Darriwilian to the Sandbian Raphiophorus survived into the Silurian 2 Taxonomy editThe subfamily Taklamakaniinae was erected to bring together the genera Nanshanaspis Pseudampyxina and Taklamakania and then later Kongqiangheia on the basis that they all have only three thoracic segments Analysis of adult anatomy of these genera and larval stages of other raphiophorids showed they most probably developed through paedomorphosis from three different ancestors so provide an example of parallel evolution Nanshanaspis closely resembles young Globampyx Pseudampyxina strongly looks like juvenile Raymondella and Taklamakania is almost identical to early stages of Ampyxina Since the three genera of the Taklamakaniinae have been demonstrated to be unrelated to each other this subfamily is regarded as polyphyletic and has been synonymized with the Raphiophorinae 3 Genera edit These genera are assigned to the Raphiophoridae 1 Subfamily Raphiophorinae Raphiophorus Angelin 1854 Ampyx Dalman 1827 Ampyxella Dean 1960 Ampyxina Ulrich 1922 Ampyxoides Whittington 1965 Bulbaspis Chugaeva 1956 Cnemidopyge Whittard 1955 Damghanampyx Ghobadi Pour Vidal amp Hosseini Nezhad 2007 Edmundsonia Cooper 1953 Globampyx Fortey 1975 Kongqiangheia Lonchodomas Angelin 1854 Mendolaspis Rusconi 1951 Nanshanaspis Chang amp Fan 1960 Pseudampyxina Ju 1983 Raymondella Reed 1935 Rhombampyx Fortey 1975 Taklamakania Zhang 1980 Subfamily Endymioniinae Endymionia Billings 1865 Ampyxinella Koroleva 1959 Ampyxinops Zhang 1979 Anisonotella Whittington 1965 Carinocranium Dean 1989 Edmundsonia Cooper 1953 Jiuxiella Zhou et al 1977 Lehnertia Vaccari et al 2006 Malongullia Webby Moors amp McLean 1970 Miaopopsis Lu et al 1965 synonym Sinampyxina Miboshania Zhang 1979 Pytine Fortey 1975 Salteria Thomson 1864 Tarimella W T Zhang 1979 may be a shumardiid ptychopariid Typhlokorynetes Shaw 1966References edit a b Fortey R A 1975 The Ordovician Trilobites of Spitsbergen II Asaphidae Nileidae Raphiophoridae and Telephinidae of the Valhallfonna Formation Norsk Polarinstitutt Skrifter Vol 162 Oslo Norsk Polarinstitutt J M Adrian 2014 20 A synopsis of Ordovician trilobite distribution and diversity In D A T Harper T Servais eds Early Palaeozoic Biogeography and Palaeogeography Memoirs of the Geological Society of London Vol 38 Geological Society of London p 490 ISBN 978 1862393738 Zhou Z Webby B D Yuan W 1995 Ordovician trilobites from the Yingan Formation of northwestern Tarim Xinjiang northwestern China Alcheringa An Australasian Journal of Palaeontology 19 1 47 72 Bibcode 1995Alch 19 47Z doi 10 1080 03115519508619098 Retrieved from https en wikipedia org w index php title Raphiophoridae amp oldid 1217417699, wikipedia, wiki, book, books, library,
