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Moulting, ontogeny and sexual dimorphism in the Cambrian ptychopariid trilobite Strenuaeva inflata from the northern Swedish Caledonides

Cederstrom, Peter; Ahlberg, Per LU ; Nilsson, Carin H.; Ahlgren, John and Eriksson, Mats LU (2011) In Palaeontology 54. p.685-703
Abstract
Three thousand seven hundred disarticulated remains together with several articulated specimens of the Cambrian Series 2 ptychopariid trilobite Strenuaeva inflata Ahlberg and Bergstrom, 1978 have been collected from the Tornetrask area, northern Sweden. The material provides significant new data on the morphology, ontogeny, moulting and enrolment of the species. Two distinct morphotypes, possibly an expression of sexual dimorphism, are recognized. The morph with a pair of bulbs in the frontal area, interpreted as brood pouches, is considered to represent females. Statistical treatment of the length/width ratio in cranidia reveals isometric growth during ontogeny for both morphotypes. The transition from the meraspid to holaspid ontogenetic... (More)
Three thousand seven hundred disarticulated remains together with several articulated specimens of the Cambrian Series 2 ptychopariid trilobite Strenuaeva inflata Ahlberg and Bergstrom, 1978 have been collected from the Tornetrask area, northern Sweden. The material provides significant new data on the morphology, ontogeny, moulting and enrolment of the species. Two distinct morphotypes, possibly an expression of sexual dimorphism, are recognized. The morph with a pair of bulbs in the frontal area, interpreted as brood pouches, is considered to represent females. Statistical treatment of the length/width ratio in cranidia reveals isometric growth during ontogeny for both morphotypes. The transition from the meraspid to holaspid ontogenetic period has been established through recognition of the successive development of the number of thoracic segments in articulated late meraspides. Throughout its life cycle, S. inflata went through 11 meraspid degrees and at least 17 holaspid growth stages. Inferred moult ensembles and exuviae reveal the successive opening of cephalic sutures and the function of the rostral plate during exuviation. As in other ellipsocephalid trilobites in which enrolment is known, the pygidium and two or three thoracic segments of S. inflata are concealed beneath the cephalon (spiral enrolment) during complete enrolment. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
ptychopariid trilobite, Strenuaeva inflata, dimorphism, enrolment, functional morphology, ontogeny, lower Cambrian, Sweden
in
Palaeontology
volume
54
pages
685 - 703
publisher
Wiley-Blackwell
external identifiers
  • wos:000290590000012
  • scopus:79956038515
ISSN
1475-4983
DOI
10.1111/j.1475-4983.2010.01021.x
language
English
LU publication?
yes
id
76af34a2-0790-4eca-9b7e-7969224b2e8d (old id 1986690)
date added to LUP
2011-06-29 10:58:47
date last changed
2017-11-12 03:16:01
@article{76af34a2-0790-4eca-9b7e-7969224b2e8d,
  abstract     = {Three thousand seven hundred disarticulated remains together with several articulated specimens of the Cambrian Series 2 ptychopariid trilobite Strenuaeva inflata Ahlberg and Bergstrom, 1978 have been collected from the Tornetrask area, northern Sweden. The material provides significant new data on the morphology, ontogeny, moulting and enrolment of the species. Two distinct morphotypes, possibly an expression of sexual dimorphism, are recognized. The morph with a pair of bulbs in the frontal area, interpreted as brood pouches, is considered to represent females. Statistical treatment of the length/width ratio in cranidia reveals isometric growth during ontogeny for both morphotypes. The transition from the meraspid to holaspid ontogenetic period has been established through recognition of the successive development of the number of thoracic segments in articulated late meraspides. Throughout its life cycle, S. inflata went through 11 meraspid degrees and at least 17 holaspid growth stages. Inferred moult ensembles and exuviae reveal the successive opening of cephalic sutures and the function of the rostral plate during exuviation. As in other ellipsocephalid trilobites in which enrolment is known, the pygidium and two or three thoracic segments of S. inflata are concealed beneath the cephalon (spiral enrolment) during complete enrolment.},
  author       = {Cederstrom, Peter and Ahlberg, Per and Nilsson, Carin H. and Ahlgren, John and Eriksson, Mats},
  issn         = {1475-4983},
  keyword      = {ptychopariid trilobite,Strenuaeva inflata,dimorphism,enrolment,functional morphology,ontogeny,lower Cambrian,Sweden},
  language     = {eng},
  pages        = {685--703},
  publisher    = {Wiley-Blackwell},
  series       = {Palaeontology},
  title        = {Moulting, ontogeny and sexual dimorphism in the Cambrian ptychopariid trilobite Strenuaeva inflata from the northern Swedish Caledonides},
  url          = {http://dx.doi.org/10.1111/j.1475-4983.2010.01021.x},
  volume       = {54},
  year         = {2011},
}