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Publications (10 of 178) Show all publications
Zhang, Z., Popov, L. E., Holmer, L. E. & Zhang, Z. (2018). Earliest ontogeny of early Cambrian acrotretoid brachiopods: first evidence for metamorphosis and its implications. BMC Evolutionary Biology, 18, Article ID 42.
Open this publication in new window or tab >>Earliest ontogeny of early Cambrian acrotretoid brachiopods: first evidence for metamorphosis and its implications
2018 (English)In: BMC Evolutionary Biology, ISSN 1471-2148, E-ISSN 1471-2148, Vol. 18, article id 42Article in journal (Refereed) Published
Abstract [en]

Our understanding of the ontogeny of Palaeozoic brachiopods has changed significantly during the last two decades. However, the micromorphic acrotretoids have received relatively little attention, resulting in a poor knowledge of their ontogeny, origin and earliest evolution. The uniquely well preserved early Cambrian fossil records in South China provide a great new opportunity to investigate the phylogenetically important ontogeny of the earliest acrotretoid brachiopods, and give new details of the dramatic changes in anatomy of acrotretoid brachiopods during the transition from planktotrophic larvae to filter feeding sedentary juveniles.

National Category
Other Earth and Related Environmental Sciences
Research subject
Earth Science with specialization in Historical Geology and Palaeontology
Identifiers
urn:nbn:se:uu:diva-347440 (URN)10.1186/s12862-018-1165-6 (DOI)000428944000002 ()29609541 (PubMedID)
Funder
Swedish Research Council, 2012–1658
Available from: 2018-04-02 Created: 2018-04-02 Last updated: 2018-06-13Bibliographically approved
Holmer, L. E., Popov, L. E., Ghobadi Pour, M., Claybourn, T., Zhang, Z., Brock, G. A. & Zhang, Z. (2018). Evolutionary significance of a middle Cambrian (Series 3) in situ occurrence of the pedunculate rhynchonelliform brachiopod Nisusia sulcata. Lethaia: an international journal of palaeontology and stratigraphy
Open this publication in new window or tab >>Evolutionary significance of a middle Cambrian (Series 3) in situ occurrence of the pedunculate rhynchonelliform brachiopod Nisusia sulcata
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2018 (English)In: Lethaia: an international journal of palaeontology and stratigraphy, ISSN 0024-1164, E-ISSN 1502-3931Article in journal (Refereed) Epub ahead of print
Abstract [en]

Exceptionally preserved, silicified and articulated complete shells of the rhynchonelliform kutorginate brachiopod Nisusia sulcata are redescribed from the middle Cambrian (Series 3) Marjum Limestone, Utah. Cylindroid sausage-like protrusions, emerging posteriorly between the valves, were originally interpreted as faecal in origin, but restudy under the SEM shows that these features represent silicified pedicles as they are attached in situ to other Nisusia. The Nisusia host most likely was alive at the time of attachment. Restudy of the pedicles of Nisusia provides new phylogenetic information on the anatomy of the earliest rhynchonelliforms. The silicified pedicles differ considerably from the pedicles of living crown group rhynchonelliforms in being strongly annulated, distally tapering, and were likely to have been rather more flexible. The Nisusia pedicles are more similar to the exceptionally preserved pedicles from other Cambrian rhynchonelliform brachiopods, including Kutorgina, Longtancunella and Alisina, but these emerge from the ventral apical foramen rather than from between the valves as in Nisusia. Although generally similar, these two types of pedicles are unlikely to represent homologous structures as Nisusia is provided with both an apical foramen (possibly larval attachment) and a posterior adult pedicle. The similarities may be explained by similar type of accretionary growth from two different types of epithelia. The Nisusia-like pedicle appeared early within the kutorginates and rhynchonellates. The discovery of hollow spines in Nisusia sulcata further supports the generic assignation of the species.

Keyword
Brachiopoda, Cambrian, Kutorginata, Nisusia, pedicle, Rhynchonelliformea
National Category
Earth and Related Environmental Sciences
Research subject
Earth Science with specialization in Historical Geology and Palaeontology
Identifiers
urn:nbn:se:uu:diva-338433 (URN)10.1111/let.12254 (DOI)
Available from: 2018-01-09 Created: 2018-01-09 Last updated: 2018-01-22Bibliographically approved
Zhang, Z., Zhang, Z., Holmer, L. E. & Chen, F. (2018). Post-metamorphic allometry in the earliest acrotretoid brachiopods from the lower Cambrian (Series 2) of South China, and its implications. Palaeontology, 61(2), 183-207
Open this publication in new window or tab >>Post-metamorphic allometry in the earliest acrotretoid brachiopods from the lower Cambrian (Series 2) of South China, and its implications
2018 (English)In: Palaeontology, ISSN 0031-0239, E-ISSN 1475-4983, Vol. 61, no 2, p. 183-207Article in journal (Refereed) Published
Abstract [en]

The earliest growth of post-metamorphic (post-larval) shells in two species of Eohadrotreta is described from the Cambrian Shuijingtuo Formation of South China. Two different growth patterns can be observed by quantifying developmental variations in size and shape of successive stages of post-metamorphic shell growth (including the pedicle foramen forming stage, pedicle foramen enclosing stage and intertrough increasing stage) of Eohadrotreta zhenbaensis and Eohadrotreta? zhujiahensis. The pedicle foramen is never enclosed within the metamorphic shell of E. zhenbaensis, while the enclosed pedicle foramen of E.? zhujiahensis is located directly outside the metamorphic shell after the pedicle foramen enclosing stage. A strongly allometric growth pattern of E. zhenbaensis is demonstrated by the early enclosure of the pedicle foramen; an accelerated lengthening of the ventral intertrough is associated with the development of a more complex dorsal median septum during the intertrough increasing stage. By contrast, E.? zhujiahensis demonstrates possible paedomorphic development by delayed enclosure of pedicle foramen and an associated decreased lengthening of ventral intertrough during the intertrough increasing stage. This ontogenetic developmental sequence represents the marginal accretionary formation and growth of the pedicle foramen, which resembles that of linguloid brachiopods. Furthermore, the developmental process of the pedicle foramen of Eohadrotreta seems to recapitulate the likely evolutionary transition from the Botsfordiidae, with open delthyrium, to the Acrotheloidea, with an enclosed foramen. This study provides a unique opportunity to obtain a complete understanding of the ontogenetic development of the earliest acrotretoids, and casts new light on the phylogeny of lingulate brachiopods.

Keyword
ontogeny, allometry, acrotretoid brachiopods, Eohadrotreta, heterochrony, lower Cambrian
National Category
Natural Sciences
Research subject
Earth Science with specialization in Historical Geology and Palaeontology
Identifiers
urn:nbn:se:uu:diva-333370 (URN)10.1111/pala.12333 (DOI)000424831500003 ()
Funder
Swedish Research Council, 2012-1658
Available from: 2017-11-12 Created: 2017-11-12 Last updated: 2018-03-26Bibliographically approved
Holmer, L. E., Zhang, Z., Topper, T. P., Popov, L. & Claybourn, T. (2018). The attachment strategies of Cambrian kutorginate brachiopods: the curious case of two pedicle openings and their phylogenetic significance. Journal of Paleontology, 92(1), 33-39
Open this publication in new window or tab >>The attachment strategies of Cambrian kutorginate brachiopods: the curious case of two pedicle openings and their phylogenetic significance
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2018 (English)In: Journal of Paleontology, ISSN 0022-3360, E-ISSN 1937-2337, Vol. 92, no 1, p. 33-39Article in journal (Refereed) Published
Abstract [en]

The kutorginates are commonly the most abundant rhynchonelliform brachiopod found in the early Cambrian; they are also some of the oldest known rhynchonelliforms, first appearing in the Unnamed Series 2 (Atdabanian equivalent) and becoming extinct sometime in Cambrian Series 3 (Amgaian equivalent). Moreover, kutorginates are the first known member of the rhynchonelliforms for which we have a detailed knowledge of their soft-part anatomy, including the lophophore, digestive tract, and pedicle—all exceptionally preserved in Kutorgina chengjiangensis Zhang et al., 2007 from the early Cambrian Chengjiang Lagerstätte of southern China. The stout and annulated pedicle in the original report was described as protruding between the valves; however, newly collected better-preserved material now clearly shows that the pedicle actually protrudes from the apical perforation of Kutorgina chengjiangensis. This type of apical pedicle has also been described from other early Cambrian rhynchonelliforms, including the problematic chileate Longtancunella chengjiangensis (Zhang et al., 2011a). Exceptionally preserved similar pedicles are also known to emerge apically from the Silurian chileate dictyonellid Eichwaldia subtrigonalis Billings, 1858, as well as from the recently described Silurian chileate Trifissura rigida Holmer, Popov, and Bassett, 2014. However, it is clear that the only other exceptionally preserved kutorginate—a silicified Nisusia—was provided with an adult pedicle emerging between the valves from a posterior gap; thus, Nisusia has two pedicle openings. However, the apical foramen may represent the earliest attachment of the larvae, which subsequently became nonfunctional through ontogeny. It is suggested that both types of attachment strategies may have appeared early in the stem lineage of the Rhynchonelliformea.

National Category
Other Earth and Related Environmental Sciences
Research subject
Earth Science with specialization in Historical Geology and Palaeontology
Identifiers
urn:nbn:se:uu:diva-330871 (URN)10.1017/jpa.2017.76 (DOI)000425398500005 ()
Funder
Swedish Research Council, 2012-1658
Available from: 2017-10-05 Created: 2017-10-05 Last updated: 2018-04-24Bibliographically approved
Harper, D. A. T., Popov, L. E. & Holmer, L. E. (2017). Brachiopods: origin and early history. Palaeontology, 60(5), 609-631
Open this publication in new window or tab >>Brachiopods: origin and early history
2017 (English)In: Palaeontology, ISSN 0031-0239, E-ISSN 1475-4983, Vol. 60, no 5, p. 609-631Article in journal (Refereed) Published
Abstract [en]

Despite many major advances in recent years, three key challenges remain in bringing clarity to the early history of the phylum: (1) identifying the origin, morphology and life modes of the first brachiopods; (2) understanding the relationships of the major groups to each other and higher sister taxa; and (3) unravelling the roles of the Cambrian and Ordovician radiations that set the agenda for much of subsequent brachiopod evolution. Since some 95% of all brachiopod taxa are extinct, the fossil record is the primary source of data to frame and test models for the evolution of the phylum. The acquisition of new, and the redescription of existing faunas, in precise spatial and temporal frameworks, using new and well-established analytical and investigative techniques, are as important as ever.

Keyword
brachiopod, Cambrian, Ordovician, phylogeny, diversity
National Category
Zoology
Research subject
Earth Science with specialization in Historical Geology and Palaeontology
Identifiers
urn:nbn:se:uu:diva-325928 (URN)10.1111/pala.12307 (DOI)000408773000001 ()
Funder
Swedish Research Council, VR 2012-1658The Wenner-Gren Foundation
Available from: 2017-06-29 Created: 2017-06-29 Last updated: 2017-11-29Bibliographically approved
Topper, T. P., Strotz, L. C., Skovsted, C. B. & Holmer, L. E. (2017). Do brachiopods show substrate-related phenotypic variation?: A case study from the Burgess Shale. Palaeontology, 60(2), 269-279
Open this publication in new window or tab >>Do brachiopods show substrate-related phenotypic variation?: A case study from the Burgess Shale
2017 (English)In: Palaeontology, ISSN 0031-0239, E-ISSN 1475-4983, Vol. 60, no 2, p. 269-279Article in journal (Refereed) Published
Abstract [en]

As sessile, benthic filter feeders, brachiopods share an intimate relationship with their chosen substrate. Individuals of Micromitra burgessensis in the Burgess Shale Formation are preserved in life position, attached to a range of hard substrates, including skeletal debris, conspecific brachiopods, sponges and enigmatic tubes. Here we investigate the phenotypic variability of M.burgessensis associated with differing substrate attachments. We apply geometric morphometrics to test for variation by plotting landmarks on the exterior of ventral and dorsal valves of M.burgessensis specimens that are preserved attached to different substrates. Using principal component, canonical variate analyses and anova, we determine that there is some variation in shape related to substrate. Canonical variate analyses, for ventral valves and dorsal valves, indicate that specimens attached to the same substrate are recognizable in shape from specimens attached to other substrate types. The strength of differentiation however, is not robust and combined with our discriminate analysis of separate populations suggests that there is the potential for substrates to exercise only weak control over the morphology of Brachiopoda.

Keyword
substrate, brachiopod, phenotypic variation, geometric morphometrics, Burgess Shale, morphology
National Category
Geosciences, Multidisciplinary
Research subject
Earth Science with specialization in Historical Geology and Palaeontology
Identifiers
urn:nbn:se:uu:diva-315497 (URN)10.1111/pala.12281 (DOI)000394993300010 ()
Funder
Swedish Research Council, VR 2009-4395 2012-1658
Available from: 2017-02-15 Created: 2017-02-15 Last updated: 2017-04-20Bibliographically approved
Holmer, L. E., Ghobadi Pour, M., Popov, L. E., Zhang, Z. & Zhang, Z. (2017). Ecology, biofacies, biogeography and systematics of micromorphic lingulate brachiopods from the Ordovician (Darriwilian–Sandbian) of south-central China. Papers in Palaeontology, 3(3), 317-361
Open this publication in new window or tab >>Ecology, biofacies, biogeography and systematics of micromorphic lingulate brachiopods from the Ordovician (Darriwilian–Sandbian) of south-central China
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2017 (English)In: Papers in Palaeontology, ISSN 2056-2802, Vol. 3, no 3, p. 317-361Article in journal (Refereed) Published
Abstract [en]

Ordovician (Darriwilian to Sandbian) micromorphic linguliform lingulate brachiopods are described from the Guniutan Formation at the Fenxiang section in Hubei province, and the Maocaopu and Cili sections in Hunan province of south-central China, situated on the Yangtze Platform. A total of 7560 specimens from 155 limestone samples (within the interval of Lenodus variabilis – Pygodus anserinus biozones) are assigned to 22 species, representing a low taxonomic diversity and low abundance fauna. The fauna is dominated by the Acrotretoidea, mainly species of the Torynelasmatidae, with Torynelasma the most abundant (more than 40% of total number of specimens), along with the Eoconulidae and Eoconulus (18% of total) representing the second most common forms. Species of the Ephippelasmatidae are also common (16% of total) diverse, and include representatives of Myotreta and Numericoma, as well as Ephippelasma, whereas species of the Scaphelasmatidae are somewhat less common (13% of total). All three investigated sections represent outer shelf environments, but the Maocaopu section is situated in a relatively deeper position, in proximity of the south-eastern outer margin of the Upper Yangtze Platform, close to its boundary with the Jiangnan Slope. A quantitative analysis of the relative abundance data was carried out in order to investigate the biofacies distribution of the micromorphic brachiopod communities across the Yangtze Platform, something that has not been attempted before with Palaeozoic linguliforms. Six lingulate microbrachiopod communities could be recognized in the sections. The major biofacies shift, which occurred in the Cili section in the upper part of the Microzarkodina ozarkodella Zone, at the time of the onset and initial rise of the Mid Darriwilian Carbon Isotope Excursion (MDICE) suggests that these biofacies may have been depth controlled.

Keyword
Ordovician, Linguliformea, brachiopod, China, ecology, biogeography
National Category
Geology
Identifiers
urn:nbn:se:uu:diva-318598 (URN)10.1002/spp2.1077 (DOI)000406695100001 ()
Funder
Swedish Research Council, 2012-1658; 2009-4395
Available from: 2017-03-27 Created: 2017-03-27 Last updated: 2017-11-06Bibliographically approved
Altenburger, A., Martinez, P., Budd, G. E. & Holmer, L. E. (2017). Gene Expression Patterns in Brachiopod Larvae Refute the "€œBrachiopod-Fold"€ Hypothesis. Frontiers in Cell and Developmental Biology, 5, 1-3, Article ID 74.
Open this publication in new window or tab >>Gene Expression Patterns in Brachiopod Larvae Refute the "€œBrachiopod-Fold"€ Hypothesis
2017 (English)In: Frontiers in Cell and Developmental Biology, Vol. 5, p. 1-3, article id 74Article in journal (Refereed) Published
Keyword
Brachiopoda, body plan, evolution, brachiopod fold, gene expression, ontogeny
National Category
Biological Sciences
Research subject
Earth Science with specialization in Historical Geology and Palaeontology
Identifiers
urn:nbn:se:uu:diva-328337 (URN)10.3389/fcell.2017.00074 (DOI)
Funder
Swedish Research Council, 2012-1658
Available from: 2017-08-22 Created: 2017-08-22 Last updated: 2017-08-22Bibliographically approved
Holmer, L. E. (2017). Kambrosiluren i Västergötland – en geologisk resa genom tid och rum. In: Christer Ask (Ed.), Sten - en tidsresa: . Västergötlands Fornminnesförening
Open this publication in new window or tab >>Kambrosiluren i Västergötland – en geologisk resa genom tid och rum
2017 (Swedish)In: Sten - en tidsresa / [ed] Christer Ask, Västergötlands Fornminnesförening , 2017Chapter in book (Other (popular science, discussion, etc.))
Place, publisher, year, edition, pages
Västergötlands Fornminnesförening, 2017
Series
Västergötlands fornminnesförenings tidskrift, ISSN 0347-4402 ; 2015-2016
National Category
Natural Sciences
Research subject
Earth Science with specialization in Historical Geology and Palaeontology
Identifiers
urn:nbn:se:uu:diva-321524 (URN)
Available from: 2017-05-07 Created: 2017-05-07 Last updated: 2017-05-09Bibliographically approved
Jin, J. & Holmer, L. E. (2017). Pentameroid brachiopod Karlsorus new genus from the upper Wenlock (Silurian) Slite Beds, Gotland, Sweden. Journal of Paleontology, 91(5), 911-918
Open this publication in new window or tab >>Pentameroid brachiopod Karlsorus new genus from the upper Wenlock (Silurian) Slite Beds, Gotland, Sweden
2017 (English)In: Journal of Paleontology, Vol. 91, no 5, p. 911-918Article in journal (Refereed) Published
Abstract [en]

Karlsorus n. gen. is proposed in this study as a large, smooth-shelled pentameride brachiopod of thefamily Pentameridae, based on Pentamerus gothlandicus Lebedev, 1892, from the Wenlock (Silurian) Slite bedsof Gotland, Sweden. This species is transferred from Pentamerus to the new genus because of the combination of aPentamerus-like shell shape and the development of a brachiophorium through fusion of the outer hinge plates in themiddle portion, like a dorso-ventrally inversed cruralium. The first appearance of brachiophorium in pentamerids isin the late Wenlock, known also in Brooksina, Pentamerifera, and other related pentamerid genera, marking asignificant stage in morphological transformation of dorsal internal structures, as part of the Silurian pentameridediversification in both level-bottom and reefal depositional environments.

Place, publisher, year, edition, pages
Cambridge University Press, 2017
National Category
Natural Sciences
Research subject
Earth Science with specialization in Historical Geology and Palaeontology
Identifiers
urn:nbn:se:uu:diva-328028 (URN)10.1017/jpa.2017.46 (DOI)000409050200005 ()
Funder
Swedish Research Council, 2012-1658
Available from: 2017-08-16 Created: 2017-08-16 Last updated: 2018-01-04Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-3629-0049

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