Trilobiten.de

[Jens]

Die Trilobiten-Ontogenie ist ziemlich spannendes Thema mit dem ich mich irgendwann auch mal näher beschäftigen möchte. Rudy Lerosey-Aubril (den manche auch unter dem Nickname Barracudaaa kennen) hat dies schon getan und präsentiert auf seiner neuen Homepage auch eine Menge an Referenzen zum Thema. Seine Liste habe ich kopiert und gedenke sie zu ergänzen.

Hier ein Link zur Seite (die sich noch im Aufbau befindet)

http://www.geocities.com/barracudaaa/leroseyaubril.html


Literatur von Barracudaaa zur Trilobiten-Ontogenie

http://www.geocities.com/barracudaaa/references.html

ADRAIN, J.M. & B.D.E. CHATTERTON. 1995. Aulacopleurine trilobites from the Llandovery of northwestern Canada. Journal of Paleontology, 69(2): 326-340.

ADRAIN, J.M. & B.D.E. CHATTERTON. 1995. The otarionine trilobites Harpidella and Maurotarion, with species from Northwestern Canada, the United States, and Australia. Journal of Paleontology, 69(2): 307-326.

BEECHER, C.E. 1893. A larval form of Triarthrus. American Journal of Science, 46(3): 361-362.

BEECHER, C.E. 1893. Larval forms of trilobites from the Lower Helderberg Group. American Journal of Science, 46(3): 142-147.

BEECHER, C.E. 1895. The larval stages of Trilobites. The American Geologist, 16(3): 166-197.

BERARD, P., E.N.K. CLARKSON, et al. 2000. The ontogeny of Taihungshania miqueli (Bergeron, 1893) from the Arenig of the Montagne Noire, southern France. Transactions of the Royal Society of Edinburgh, 90: 147-163.

CHATTERTON, B.D.E. 1971. Taxonomy and ontogeny of Siluro-Devonian trilobites from near Yass, New South Wales. Palaeontographica (A), 137: 1-108.

CHATTERTON, B.D.E. & S.E. SPEYER. 1990. Applications of the study of trilobite ontogeny. In: Short courses in Paleontology N°3: Arthropod Paleobiology: 116-136.

CHATTERTON, B.D.E., D.J. SIVETER , et al. 1990. Larvae and relationships of the Calymenina (Trilobita). Journal of Paleontology, 64(2): 255-277.

CHATTERTON, B.D.E., G.D. EDGECOMBE , et al. 1994. Ontogeny and relationships of Trinucleoidea (Trilobita). Journal of Paleontology, 68(3): 523-540.

CHATTERTON, B.D.E., G.D. EDGECOMBE , et al. 1997. Ontogeny and relationships of the Ordovician odontopleurid trilobite Ceratocara, with new species from Argentina and New York. Journal of Paleontology, 71(1): 108-125.

CHATTERTON, B.D.E., G.D. EDGECOMBE , et al. 1998. Ontogeny and systematics of Toernquistiidae (Trilobita, Proetida) from the Ordovician of the Argentine precordillera. Journal of Paleontology, 72(2): 273-303.

CLARKSON, E.N.K. & C.M. TAYLOR. 1995. Ontogeny of the trilobite Olenus wahlenbergi Westergard, 1922 from the upper Cambrian Alum Shales of Andrarum, Skane, Sweden. Transactions of the Royal Society of Edinburgh, 86: 13-34.

CLARKSON, E.N.K., C.M. TAYLOR, et al. 1997. Ontogeny of the trilobite Parabolina spinulosa (Wahlenberg, 1818) from the upper Cambrian Alum Shales of Sweden. Transactions of the Royal Society of Edinburgh, 88: 69-89.

CLARKSON, E.N.K. & P. AHLBERG. 2002. Ontogeny and structure of a new, miniturised and spiny Olenid trilobite from Southern Sweden. Palaeontology, 45(1): 1-22.

CLARKSON, E.N.K., J. AHLGREN, et al. 2003. Ontogeny, structure and functional morphology of some spiny Ctenopyge species (Trilobita) from the upper Cambrian of Västergötland, Sweden. Trans. of the Royal Society of Edinburgh, 94: 115-143.

DAHMS, H.-U. 2000. Phylogenetic implications of the Crustacean nauplius. Hydrobiologia, 417: 91-99.

EDGECOMBE, G.D. & B.D.E. CHATTERTON. 1987. Heterochrony in the Silurian radiation of encrinurine trilobites. Lethaia, 20: 337-351.

EDGECOMBE, G.D., S.E. SPEYER , et al. 1988. Protaspid larvae and phylogenetics of encrinurid trilobites. Journal of Paleontology, 62(5): 779-799.

EDGECOMBE, G.D. & B.D.E. CHATTERTON. 1992. Early Silurian (LLandovery) Encrinurine Trilobites from the Mackenzie Moutains, Canada. Journal of Paleontology, 66(1): 52-74.

EDGECOMBE, G.D., B.D.E. CHATTERTON, et al. 1997. Ontogeny of the proetoid trilobite Stenoblepharum, and relationships of a new species from the Upper Ordovician of Argentina. Journal of Paleontology, 71(3): 419-433.

EDGECOMBE, G.D., B.D.E. CHATTERTON, et al. 1998. Ordovician (Whiterock) Calymenid and Encrinurid Trilobites from the precordillera of Argentina. Journal of Paleontology, 72(4): 678-697.

EDGECOMBE, G.D., B.D.E. CHATTERTON, et al. 1999. Ordovician Cheirurid trilobites from the Argentine precordillera. Journal of Paleontology, 73(6): 1155-1175.

EDGECOMBE , G.D., B.D.E. CHATTERTON, et al. 1999. Ordovician Pliomerid and Prosopiscid trilobites from Argentina. Journal of Paleontology, 73(6): 1144-1154.

EVITT, W.R. 1961. Early ontogeny in the trilobite family Asaphidae. Journal of Paleontology, 35(5): 986-995.

FEIST, R. 1970. Breviscutellum (Meridioscutellum) n.sg. (Trilobite) et son développement larvaire. Geobios, 3(4): 41-73.

FORTEY, R.A. & B.D.E. CHATTERTON. 1988. Classification of the trilobite suborder Asaphina. Palaeontology, 31(1): 165-222.

HU, C.-H. 1970. The ontogenies of Ponumia obscura (Lochman), N.G., and of Housia canadensis (Walcott) (Trilobita) from the Upper Cambrian of the Big Horn Mountains, Wyoming. Trans.Proc.Palaeont.Soc.Japan, 77: 253-264.

HU, C.-H. 1971. Ontogeny and sexual dimorphism of Lower Paleozoic Trilobita. Palaeontographica Americana, 7(44): ?.

HU, C.-H. 1974. Ontogenies of two Middle Ordovician from Edinburg Formation of Virginia. Trans.Proc.Palaeont.Soc.Japan, 95: 353-363.

HU, C.-H. 1975. Ontogenies of four species of silicified Middle Ordovician trilobites from Virginia. Proceedings of the Geological Society of China, 18: 115-127.

HU, C.-H. 1976. Ontogenies of three species of silicified Middle Ordovician trilobites from Virginia. Trans.Proc.Palaeont.Soc.Japan, 101: 247-263.

HU, C.-H. 1984. Ontogenesis of Ehmaniella burgessensis Rasetti (Trilobita) from Burgess shale, Middle Cambrian, Yoho park, British Columbia. Trans. Proc. Palaeont. Soc. Japan, 135: 395-400.

HU, C.-H. 1985. Ontogenetic development of Cambrian trilobites from British Columbia and Alberta, Canada (Part I). Journ. Taiwan Museum, 38(2): 121-158.

HU, C.-H. 1985. Ontogenies of two Middle Cambrian corynexochid trilobites from the Canadian Rocky Mountains. Trans. Proc. Palaeont. Soc. Japan, 138: 138-147.

HU, C.-H. 1986. Ontogenetic development of Cambrian trilobites from British Columbia and Alberta, Canada (Part II). Journ. Taiwan Museum, 39(1): 1-44.

KOPASKA-MERKEL, D.C. 1981. Ontogeny of Ehmaniella: implications for trilobite ecology. United State Geological Survey, Open-file Report, vol. 81-743: 111-114.

LALICKER, C.G. 1935. Larval stages of trilobites from the Middle Cambrian of Alabama. Journal of Paleontology, 9(5): 394-399.

LEE, D.-C. & B.D.E. CHATTERTON. 1996. Terminology of glabellar lobes in trilobites larvae based on homology. Journal of Paleontology, 70(3): 439-442.

LEE, D.-C. & B.D.E. CHATTERTON. 1997. Hystricurid trilobite larvae from the Garden City Formation (Lower Ordovician) of Idaho and their phylogenetic implications. Journal of Paleontology, 71(5): 862-877.

LEE, D.-C. & B.D.E. CHATTERTON. 1997. Ontogenies of trilobites from the Lower Ordovician Garden City Formation of Idaho and their implications for the phylogeny of the Cheirurina. Journal of Paleontology, 71(4): 683-791.

LEE, D.-C. & B.D.E. CHATTERTON. 1997. Three new proetide trilobite larvae from the Lower Ordovician Garden City Formation in Southern Idaho. Journal of Paleontology, 71(3): 434-441.

LEE, D.-C. & B.D.E. CHATTERTON. 2003. Protaspides of Leiostegium and their implications for membership of the order Corynexochida. Palaeontology, 46(3): 431-445.

LEROSEY-AUBRIL, R. & R. FEIST. 2005. First Carboniferous protaspid larvae (Trilobita). Journal of Paleontology, 79(4): 702-718.

LUDVIGSEN, R. & B.D.E. CHATTERTON. 1980. The ontogeny of Failleana and the origin of the Bumastinae (Trilobita). Geological Magazine, 117(5): 471-478.

LUDVIGSEN, R. & R.P. TRIPP. 1990. Silurian trilobites from the Northern Yukon Territory. Life Sciences Contributions (Royal Ontario Museum Toronto), 153: 1-59.

MCNAMARA , K.J., F. YU, et al. 2003. Ontogeny and heterochrony in the oryctocephalid trilobite Arthricocephalus from the Early Cambrian of China. Special papers in Palaeontology, 70: 103-126.

OWENS, R.M. 1974. The affinities of the trilobite genus Scharyia, with a description of two new species. Palaeontology, 17: 685-697.

PALMER, A.R. 1962. Comparative ontogeny of some opisthoparian, gonatoparian and proparian Upper Cambrian trilobites. Journal of Paleontology, 36(1): 87-96.

RASETTI, F. 1954. Phylogeny of the Cambrian trilobite family Catellicephalidae and ontogeny of Welleraspis. Journal of Paleontology, 28(5): 599-612.

RAYMOND, P.E. 1935. Protaspides of trilobites. Journal of Paleontology, 9(5): 400-401.

ROSS, R.J.J. 1951. Ontogenies of three Garden City (Early Ordovician) trilobites. Journal of Paleontology, 25(5): 578-586.

ROSS, R.J.J. 1951. Stratigraphy of the Garden City Formation in northeastern Utah, and its trilobite faunas. Bulletin of the Peabody Museum of Natural History, Yale University, 6: 1-161.

ROSS, R.J.J. 1953. Additional Garden City (Early Ordovician) trilobites. Journal of Paleontology, 27(5): 633-646.

SHERGOLD, J.H. 1991. Protaspid and early meraspid growth stages of the eodiscoid trilobite Pagetia ocellata Jell, and their implications for classification. Alcheringa, 15: 65-86.

SNAJDR, M. 1981. Ontogeny of some representatives of the trilobite genus Scharyia. Journal of Geological Sciences (Paleontology), 24: 7-35.
SPEYER, S.E. & B.D.E. CHATTERTON. 1990. Trilobite larvae, larval ecology and developmental paleobiology. In Short courses in Paleontology N°3: Arthropod Paleobiology: 137-156.

STORMER, L. 1942. Studies on trilobite morphology, part II : the larval development, the segmentation and the sutures, and their bearing on trilobite classification. Norsk Geologisk Tidsskrift, 21: 49-164.

STUBBLEFIELD, C.J. 1926. Notes on the development of Shumardia pusilla. Linnean Society Journal of Zoology, 36: 345-372.

TAYLOR, M.E. 1976. Indigenous and redeposited trilobites from Late Cambrian basinal environments of Central Nevada. Journal of Paleontology, 50(4): 668-700.

TRIPP, R.P. & W.R. EVITT. 1981. Silicified Lichidae (Trilobita) from the Middle Ordovician of Virginia. Geological Magazine, 118(6): 665-677.

TRIPP, R.P. & W.R. EVITT. 1983. Silicified trilobites of the genus Dimeropyge from the Middle Ordovician of Virginia. Special Papers in Paleontology, 30: 229-240.

TRIPP, R.P., D.M. RUDKIN, et al. 1997. Silicified trilobites of the genus Sphaerocoryphe from the Middle Ordovician of Virginia. Canadian Journal of Earth Sciences, 34: 770-788.

WAISFELD, B.G., N.E. VACCARI, et al. 2001. Systematics of Shumardiidae (Trilobita), with new species from the Ordovician of Argentina. Journal of Paleontology, 75(4): 827-859.

WENWEI, Y., Z. ZHIYI, et al. 2003. The ontogeny of the Ordovician trilobite Ovocephalus and its bearing on the affinity and evolution of the genus. Special papers in Palaeontology, 70: 259-269.

WHITTINGTON, H.B. 1941. Silicified Trenton trilobites. Journal of Paleontology, 15(5): 492-522.

WHITTINGTON, H.B. 1956. Silicified Middle Ordovician trilobites: the Odontopleuridae. Bulletin of the Museum of Comparative Zoology, 114(5): 155-288.

WHITTINGTON, H.B. 1965. Trilobites of the Ordovician Table Head Formation, Western Newfoundland. Bulletin of the Museum of Comparative Zoology, 132(4): 275-442.

WHITTINGTON, H.B. & S.W. CAMPBELL. 1967. Silicified Silurian trilobites from Maine. Bulletin of the Museum of Comparative Zoology, 135(9): 447-483.

ZHANG, X.-G. 1987. Moult stages and dimorphism of Early Cambrian bradoriids from Xichuan, Henan, China. Alcheringa, 11: 1-19.

ZHANG, X.-G. 1989. Ontogeny of an Early Cambrian eodiscoid trilobite from Henan, China. Lethaia, 22: 13-29.

ZHANG, X.-G. & E.N.K. CLARKSON. 1993. Ontogeny of the eodiscid trilobite Shizhudiscus longquanensis from the Lower Cambrian of China. Palaeontology, 36(4): 785-806.

ZHANG, X.-G. & B.R. PRATT. 1999. Early Cambrian trilobite larvae and ontogeny of Ichangia ichangensis Chang, 1957 (Protolenidae) from Henan, China. Journal of Paleontology, 73(1): 117-128.

Danke an Barracudaaa,

Grüsse,

Jens

[Jens]

Hier nun ein paar Ergänzungen:

einige Artikel wurde schon genannt, hier aber nun mit Abstracts:


Brian D. E. Chatterton, Gregory D. Edgecombe, Norberto E. Vaccari, and Beatriz G. Waisfeld (1999): Ontogenies of some Ordovician Telephinidae from Argentina, and larval patterns in the Proetida (Trilobita)
Journal of Paleontology, 73 (2): 219 - 239.

Abstract:

The ontogenies of three new species of Telephinidae, Telephina calandria, Telephina chingolo, and Telephina problematica are described from Arenig-Caradoc strata in the Argentine Precordillera, and compared with the larval stages of some other Proetida, including other telephinids. New findings reveal 1) a radical metamorphosis in the ontogenies of these Telephina species late in the meraspid period, not previously described among Trilobita; and 2) distinctive hypostomes of Telephinidae containing long, thin anterolaterally and dorsally splayed anterior wings. Early ontogenies of different species currently assigned to the genus Telephina fall into at least two distinct morphological and life history groups, and hypostomes (if correctly assigned in previous works) vary significantly. The three new species strengthen the hypothesis of a phylogenetic connection between Oopsites and Telephina. Three morphological types of protaspid instars are described for proetide trilobites. Two are anaprotaspides, and the third is a metaprotaspis. They always occur in the same sequence in the ontogeny, but no cases are known of all three types in the same species. These larval types are important for understanding the systematics and life cycles of the Proetida. Benthic/pelagic transitions identify four life history patterns among the the Proetida. The best larval synapomorphy for the Proetida is the distinctive metaprotaspid larval type, which is absent in very few proetides (some Telephinidae), perhaps as a result of heterochronic displacement of this stage into the meraspid period.


Catherine Cronier, Sabrina Renaud, Raimund Feist, and Jean-Christophe Auffray (1998): Ontogeny of Trimerocephalus lelievrei (Trilobita, Phacopida), a representative of the Late Devonian phacopine paedomorphocline; a morphometric approach. - Paleobiology; 24 (3): 359-370.

Abstract:

A detailed morphometric approach based on size and on outline analyses has been used on an exceptionally well-preserved assemblage of silicified trilobite exuvia, recovered from a Late Devonian limestone from southeastern Morocco. The material comprises a series of late larval to postlarval growth stages belonging to a single phacopine species, Trimerocephalus lelievrei Cronier and Feist, 1997. Plurimodality of size distribution has allowed us to discriminate postlarval instars. Distinct dimensional classes of isolated parts are obtained using the intertooth distances on the posterior pygidial margin and the internotch distances in the cephalic vincular furrow, which are functionally linked during trilobite enrollment. Morphometric analysis of development permitted demonstration of progressive shape change in agreement with ontogenetic ordination and a comparison of the timing of size and shape changes. The main shape changes appear to occur early in development, and once the "adult" morphology is obtained, size increases significantly. The growth rate during ontogeny is estimated by analogy with extant deep-sea crustaceans. Exponential size increase resulting from constant duration of intermolt periods may be regarded as a life history strategy to compete in a nutrient-impoverished offshore environment. The particular phacopine mode of molting, which involves the opening of the neck joint after ankylosis of the facial sutures, occurred in Trimerocephalus lelievrei between the first two postlarval instars, later than in its ancestor. Trimerocephalus lelievrei occupies an intermediate position within the phacopine paedomorphocline as indicated by the delayed onset of ankylosis.



Gregory D. Edgecombe, Brian D. E. Chatterton, Norberto E. Vaccari, and Beatriz G. Waisfeld (1999): Ordovician Cheirurid trilobites from the Argentine precordillera. - Journal of Paleontology, 73(6): 1155-1175.

Abstract:

New cheirurid trilobite species from the Las Aguaditas Formation in San Juan Province include the Llanvirn Macrogrammus rafi, and the Early Caradoc Ceraurinella zhoui, Nieszkowskia jakei, and N. yongyii. Precordilleran species, such as the Llanvirn Macrogrammus pengi new species from the Gualcamayo Formation, reinforce sinoparapilekiinid affinities for the poorly known Macrogrammus Whittard, 1966, although the monophyly of Sinoparapilekiini requires corroboration. The ontogeny of Ceraurinella zhoui confirms the presence of early protaspid stages for this genus (and Cheirurinae in general). Rare cheirurids include species of Heliomeroides, Pateraspis, and an additional acanthoparyphinid.

GREGORY D. EDGECOMBE, BRIAN D. E. CHATTERTON, NORBERTO E. VACCARI and BEATRIZ G. WAISFELD (2005): TRIARTHRINID TRILOBITES (OLENIDAE) FROM THE MIDDLE AND UPPER ORDOVICIAN, PRECORDILLERA OF ARGENTINA. - Journal of Paleontology, 79 (1): 89-109

Dong-Chan Lee and Duck K. Choi (1999): Ontogenetic changes of Bacculae in Korean asaphid trilobites and their taxonomic implications
Journal of Paleontology, 73 (6): 1210 - 1213.


RUDY LEROSEY-AUBRIL and RAIMUND FEIST (2005): FIRST CARBONIFEROUS PROTASPID LARVAE (TRILOBITA). - Journal of Paleontology, 79 (4): 702 - 718.

Abstract:

The recovery of well-preserved silicified larvae from the early Tournaisian of Montagne Noire, southern France, allows the first description of the early ontogeny of proetoid trilobites, survivors of the end-Devonian Hangenberg extinction event. The fauna comprises various taxa that can only partly and tentatively be assigned to the genera Liobolina, Diacoryphe, and Pedinocoryphe without specific attribution. The close resemblance of these larvae to previously described proetoid larvae from the Ordovician and Devonian emphasizes the ontogenetic homogeneity of this superfamily. Moreover, it supports the view that the Proetida is composed of two clades: the Aulacopleuroidea/Bathyuroidea group and the Proetoidea. The Carboniferous anaprotaspides exhibit an unusually wide size-range that may provide evidence of the acquisition of an extended planktonic period in the early ontogeny of at least some Carboniferous proetoids. This change in the ontogenetic strategy may have enabled proetoid trilobites to survive during the end-Devonian biocrises.

LEROSEY-AUBRIL, R. & FEIST, R. (2005): Post-protaspid ontogeny of the blind cyrtosymboline Helioproetus (Trilobita) from the late Famennian of Thuringia, Germany. - Senckenbergiana lethaea, 85 (1): 119-130. (erschienen 30.6.2005)


Allison R. Palmer (1962) Comparative ontogeny of some opisthoparian, gonatoparian and proparian Upper Cambrian trilobites. - Journal of Paleontology; 36 (1): 87-96.

Abstract:

Study of silicified ontogenetic series of opisthoparian (Aphelaspis), gonatoparian (Glaphyraspis), and proparian (Hardyoides) trilobites indicates the probable homology of cephalic spines in ptychopariid trilobites. Opisthoparia, gonatoparia, and proparia are redefined in terms of differential development of cephalic spines relative to a morphologically constant course of the posterior section of the facial suture. Five protaspid instars and a probable growth rate factor of 1.08 can be demonstrated for Aphelaspis.


Keonho Kim, H. David Sheets, Robert A. Haney and Charles E. Mitchell (2002): Morphometric analysis of ontogeny and allometry of the Middle Ordovician trilobite Triarthrus becki. - Paleobiology; 28 (3): 364-377.

Abstract:

Traditionally, the distinction between meraspis and holaspis among trilobites has been based on the achievement of the full adult complement of thoracic segments. Using a large sample (over 700 specimens collected from a single bed) we explore the utility of employing the ontogenetic trajectory of the cranidium as an alternative means to differentiate trilobite growth stages. This method is particularly useful for species represented solely by exuviae and disarticulated individuals. We use geometric morphometrics to examine shape change among cranidia ranging in size from 0.9 mm to 11.6 mm in cephalic length. The 114 measured specimens exhibit a rather continuous gradation in size in which no distinct instars are evident.

The meraspid and holaspid specimens exhibit allometry when partial warp scores and uniform components of shape derived from thin-plate spline analysis are regressed onto log centroid size. To describe allometric shape change, deformation vectors from the smallest to the largest specimen in both ontogenetic stages are presented in three different superimposition settings by using a new software program. We have concluded that a new superimposition method (the Sliding Baseline Registration) is a useful tool for visualizing allometry in organisms that contain an axis of symmetry. As a result, we conclude that allometry is evident in meraspides and holaspides, but the degree of allometry in holaspides is very small relative to that in meraspides. The boundary between meraspis and holaspis in Triarthrus becki appears to correspond to a large change in the rate of ontogenetic change, but neither to a change in the direction of that trajectory nor to a cessation of ontogenetic change. This boundary also corresponds to a cranidium centroid size that matches well previous determinations that holaspis begins at about 2.8 mm in cephalic length.


Richard A. Robison (1967): Ontogeny of Bathyuriscus fimbriatus and its bearing on affinities of corynexochid trilobites. - Journal of Paleontology; 41 (1); p. 213-221.

[Jens]

ein paar Zitate zur Ontogenie von Trilobiten der Ordnung Ptychopariida

weitere Clarkson-Zitate finden sich schon in der Liste von Barracudaaa (1. Post)


Clarkson, E.N.K., Ahlgren, J. & Taylor, C.M. (2003): Structure, ontogeny, and moulting in the olenid trilobite Ctenopyge (Eoctenopyge) angusta Westergard, 1922 from the upper Cambrian of Västergötland, Sweden. - Palaeontology, 46 (1): 1-27.


G. D. EDGECOMBE, B. D. E. CHATTERTON, N. E. VACCARI, and B. G. WAISFELD (2005): TRIARTHRINID TRILOBITES (OLENIDAE) FROM THE MIDDLE AND UPPER ORDOVICIAN, PRECORDILLERA OF ARGENTINA
Journal of Paleontology, 79 (1): 89 - 109.

Abstract: Middle and Upper Ordovician Triarthrinae from the Precordillera of San Juan, Argentina, include the Whiterock/Llanvirn Porterfieldia turneri (Baldis and Pöthe, 1995) and P. acava new species, and the early Caradoc Triarthrus jachalensis (Harrington and Leanza, 1957). Each of these species is described based on silicified material, including ontogenies, from the Las Aguaditas Formation. Porterfieldia maanssonae new species from the lower member of the Gualcamayo Formation (late Arenig) at Río Gualcamayo, San Juan Province, and Río Guandacol, La Rioja Province, is closely allied to P. turneri. Two protaspid stages are present in Porterfieldia, whereas mineralized protaspid stages are apparently lacking in Triarthrus jachalensis. Triarthrus jachalensis was capable of sphaeroidal enrollment by meraspid degree 2. Precordilleran species bear closest comparison to others from Spitsbergen (Porterfieldia acava n. sp. and P. parapunctata) and Sweden/Norway (Triarthrus jachalensis and T. linnarssoni).

Palmer, Allison Ralph (1958): Morphology and ontogeny of a Lower Cambrian ptychoparioid trilobite from Nevada. - Journal of Paleontology 32 (1): 154-170.


Raw, F. (1925): The development of Leptoplastus salteri and other trilobites. - Quarterly Journal of the Geological Society of London, 81: 233-284.

Schrank, E. (1973): Trilobiten aus Geschieben der oberkambrischen Stufen 3-5. - Paläontologische Abhandlungen, Abt. A, Paläozoologie, 4: 806-857.

Strand, T. (1927): The ontogeny of Olenus gibbosus. - Norsk Geologisk Tidsskrift, 9: 320-329.

Tortello, M. F. & Clarkson, E.N.K. 2003: Ontogeny, structure and moulting of the Early Ordovician olenid trilobite Jujuyaspis keideli Kobayashi from northwestern Argentina. - Ameghiniana, 40: 257-275.

Withworth, P. H. (1970): Ontogeny of the Upper Cambrian trilobite Leptoplastus crassicornis (Westergaard) from Sweden. - Palaeontology, 13: 100-111.


Es gibt sicher noch viel mehr, werde beizeiten ergänzen.

Grüsse,

Jens

[Jens]

EVITT, W.R. 1961. Early ontogeny in the trilobite family Asaphidae. Journal of Paleontology, 35(5): 986-995.

William Robert Evitt

Abstract: The morphology and development of protaspides representing the family Asaphidae are described from silicified specimens etched from Middle Ordovician limestones of northern Virginia. Close similarities with remopleuridid protaspides described by Whittington and Ross suggest that the Asaphidae and Remopleurididae are more closely related than generally has been recognized. The asaphid protaspides represent early stages of the protaspid period, before complete differentiation of a protopygidium. For an unknown reason, the late protaspid period is not represented among the fossils, although early meraspid stages are common. The resultant "missing" interval in the recorded asaphid ontogeny appears to be the interval best represented by known remopleuridid protaspides. Evidence for and some implications of this interpretation are discussed.


Hier was Neues über Proetiden.

JONATHAN M. ADRAIN (2005): AULACOPLEURID TRILOBITES FROM THE UPPER ORDOVICIAN OF VIRGINIA. - Journal of Paleontology, 79 (3): 542-563.

Abstract:

Five species of aulacopleurid trilobites occur in rich, silicified trilobite faunas from the Upper Ordovician of Virginia: Harpidella triloba (Hu, 1975a), Strasburgaspis cona (Hu, 1971), and Strasburgaspis? n. sp. A, all from the Turinian Edinburg Formation, Harpidella whittingtoni new species, from the overlying Turinian Oranda Formation, and Harpidella evitti new species, from the Chatfieldian Martinsburg Formation. The species of Harpidella, similar to other sets of congeneric taxa known from the formations, are subtly but pervasively differentiated. In addition to qualitative differentia such as the expression of the eye socle and of pygidial tubercle rows, the species are shown to differ in cranidial and librigenal shape via landmark-based geometric morphometric analysis. The genus Strasburgaspis (type species S. cona) is new. It is assigned to Aulacopleuridae on the basis of its micropygous morphology, but it shares potential apomorphies with Brachymetopidae and could prove to be the most plesiomorphic representative of that family.


Gregory D. Edgecombe, Brian D. E. Chatterton, Norberto E. Vaccari, and Beatriz G. Waisfeld (1997): Ontogeny of the proetoid trilobite Stenoblepharum, and relationships of a new species from the Upper Ordovician of Argentina. - Journal of Paleontology, 71 (3): 419-433.

[Jens]

Bin ich gerade drüber gestolpert:

McNamara KJ (1978): Paedomorphosis in Scottish olenelid trilobites (Early Cambrian). - Palaeontology, 21: 635-655.

McNamara KJ (1981): Paedomorphosis in Middle Cambrian xystridurine trilobites from northern Australia. - Allcheringa, 5: 209-224.

Mark Webster, H. David Sheets, and Nigel C. Hughes (2001): Allometric Patterning in Trilobite Ontogeny: Testing for Heterochrony in Nephrolenellus.: 105-144. - in: Miriam Leah Zelditch [ed.] : BEYOND HETEROCHRONY - The Evolution of Development: 363p.


Grüsse,

Jens