Holmiidae is a family of trilobites, that lived during the Lower Cambrian (Atdabanian). The Holmiidae is a diverse family of eight genera containing at least 17 species. It includes some of the earliest trilobites of Baltica. Holmiidae occur throughout Baltica (Scandinavia and the eastern seaboard of the Baltic Sea) and Western Laurentia (in the Great Basin of the US and northwestern Canada), and also in Morocco.[1]
Hupé (1953) defined the Holmiidae as a subfamily (Holmiinae) within the Olenellidae containing Holmia, Kjerulfia and Bondonella. Harrington et al. (1959) excluded Kjerulfia, while assigning Schmidtiellus to it. Bergström (1973) included Holmia, Elliptocephala, Esmeraldina, Schmidtiellus and Wanneria. Repina (1979) assigned Holmia, Schmidtiellus, Kjerulfia, Elliptocephala, Bondonella, Andalusiana and Holmiella to the Holmiinae, that together with the monotypic Callaviinae comprised the Holmiidae. Palmer and Repina (1993) added Holmiella but excluded Kjerulfia, they assigned to the Callaviinae. Lieberman, who made cladistic analyses of the Olenellina and the included superfamilies, regards Andalusiana an advanced "Nevadioidea", Callavia and Bondonella as Judomioidea, and Elliptocephala and Wanneria stemgroup genera closely related to the common ancestor of the Holmiidae and the Biceratopsidae.[1]
Holmia kjerulfiSchmidtiellus Moberg in Moberg and Segerberg, 1906[1]
Relationships within the Holmiidaeedit
The eye ridges in Baltic and Moroccan Holmiidae (Holmia, Schmidtiellus) are wide, have a furrow atop the ridges, and the resulting inner band merges with the frontal lobe (L4) of the glabella without an axial furrow. This is interpreted as advanced compared with the arrangement of the simple ocular lobes of Laurentian holmiids, which are separated from the L4 by a prominent axial furrow around the glabellar outline.[6]
Descriptionedit
As with most early trilobites, Holmiidae have an almost flat exoskeleton, that is only thinly calcified, and has crescent-shaped eye ridges. As part of the Olenellina suborder, the Holmiidae lack dorsal sutures in the cephalon. Like all other members of the Olenelloidea superfamily, the eye-ridges spring from the back of the frontal lobe (L4) of the central area of the cephalon (or glabella).[1] Specifically for the Holmiidae are the following diagnostic characters. The glabella is straight-sided to somewhat constricted and mostly expands forward. The frontal lobe (or L4) is usually broad and rounded. The furrows that separate the lobes are usually curved, moderately incised, and rarely completely cross the midline. The eye ridges of Baltic holmiids are often wide with an ocular furrow, inner band merging with L4 without axial furrow. Laurentian holmiids (Montezumaspis, Palmetaspis, Grandasinus, Esmeraldina and Holmiella) have unfurrowed ocular lobes separated from L4 by axial furrow. The cephalon carries so called genal spines at the corner between the half circle front/side margin and the back margin that is roughly perpendicular to the midline. These spines extend back to at least the fourth thorax segment (T4), counted front to back. The back margin of the cephalon normally carries a node or spine (or intergenal spine), straight behind the point the eye ridge is furthest from the midline or even somewhat further out. Back margin of cephalon inside the intergenal angle transverse or directed posteriorly. The third thorax segment (T3) is not larger than the neighboring segments and does not carry larger spines. Anterior thoracic pleural spines weakly to strongly thornlike except in Kjerulfia and Grandinasus.[6]
Referencesedit
^ abcdefghijLieberman, B.S. (1999). (PDF). Bulletin of the Peabody Museum of Natural History. 45. Archived from the original (PDF) on 2016-06-24. Retrieved 2019-05-09.
^"Andalusiana Lotze 1958 (trilobite)". The Paleobiology Database.
^"Callavia Matthew 1897 (trilobite)". The Paleobiology Database.
^"Cambropallas Geyer 1993 (trilobite)". The Paleobiology Database.
^"Elliptocephala Emmons 1844". The Paleobiology Database.
^ abcdHollingsworth, J.S. (2006). "Holmiidae (Trilobita: Olenellina) of the Montezuman Stage (Early Cambrian) in Western Nevada". Journal of Paleontology. 80 (2): 309–332. doi:10.1666/0022-3360(2006)080[0309:htootm]2.0.co;2. JSTOR 4095128. S2CID 131683623.
^Ebbestad, J.O.R.; Ahlberg, P.; Høyberget, M. (2003). "Redescription of Holmia inusitata (Trilobita) from the Lower Cambrian of Scandinavia". Palaeontology. 46 (5): 1039–1054. Bibcode:2003Palgy..46.1039E. doi:10.1111/1475-4983.00332.
^"Iyouella Geyer and Palmer 1995 (trilobite)". The Paleobiology Database.
January 01, 1970
holmiidae, family, trilobites, that, lived, during, lower, cambrian, atdabanian, diverse, family, eight, genera, containing, least, species, includes, some, earliest, trilobites, baltica, occur, throughout, baltica, scandinavia, eastern, seaboard, baltic, west. Holmiidae is a family of trilobites that lived during the Lower Cambrian Atdabanian The Holmiidae is a diverse family of eight genera containing at least 17 species It includes some of the earliest trilobites of Baltica Holmiidae occur throughout Baltica Scandinavia and the eastern seaboard of the Baltic Sea and Western Laurentia in the Great Basin of the US and northwestern Canada and also in Morocco 1 HolmiidaeTemporal range Atdabanian PreꞒ Ꞓ O S D C P T J K Pg N Cambropallas telesto from Morocco Scientific classification Kingdom Animalia Phylum Arthropoda Class Trilobita Order Redlichiida Suborder Olenellina Superfamily Olenelloidea Family Holmiidae 1 Hupe 1953 Contents 1 Taxonomy 2 Genera 2 1 Relationships within the Holmiidae 3 Description 4 ReferencesTaxonomy editHupe 1953 defined the Holmiidae as a subfamily Holmiinae within the Olenellidae containing Holmia Kjerulfia and Bondonella Harrington et al 1959 excluded Kjerulfia while assigning Schmidtiellus to it Bergstrom 1973 included Holmia Elliptocephala Esmeraldina Schmidtiellus and Wanneria Repina 1979 assigned Holmia Schmidtiellus Kjerulfia Elliptocephala Bondonella Andalusiana and Holmiella to the Holmiinae that together with the monotypic Callaviinae comprised the Holmiidae Palmer and Repina 1993 added Holmiella but excluded Kjerulfia they assigned to the Callaviinae Lieberman who made cladistic analyses of the Olenellina and the included superfamilies regards Andalusiana an advanced Nevadioidea Callavia and Bondonella as Judomioidea and Elliptocephala and Wanneria stemgroup genera closely related to the common ancestor of the Holmiidae and the Biceratopsidae 1 Genera editAndalusiana Lotze 1958 2 Callavia Matthew 1897 3 Cambropallas Geyer 1993 4 Elliptocephala 5 Esmeraldina Resser and Howell 1938 1 Grandinasus Hollingsworth 2006 6 Holmia Matthew 1890 1 7 synonym Baltobergstroemia Holmiella Fritz 1972 1 Iyouella Geyer and Palmer 1995 8 Kjerulfia Kiaer 1917 1 Montezumaspis Hollingsworth 2006 6 Palmettaspis Fritz 1995 1 nbsp Holmia kjerulfiSchmidtiellus Moberg in Moberg and Segerberg 1906 1 Relationships within the Holmiidae edit The eye ridges in Baltic and Moroccan Holmiidae Holmia Schmidtiellus are wide have a furrow atop the ridges and the resulting inner band merges with the frontal lobe L4 of the glabella without an axial furrow This is interpreted as advanced compared with the arrangement of the simple ocular lobes of Laurentian holmiids which are separated from the L4 by a prominent axial furrow around the glabellar outline 6 Description editAs with most early trilobites Holmiidae have an almost flat exoskeleton that is only thinly calcified and has crescent shaped eye ridges As part of the Olenellina suborder the Holmiidae lack dorsal sutures in the cephalon Like all other members of the Olenelloidea superfamily the eye ridges spring from the back of the frontal lobe L4 of the central area of the cephalon or glabella 1 Specifically for the Holmiidae are the following diagnostic characters The glabella is straight sided to somewhat constricted and mostly expands forward The frontal lobe or L4 is usually broad and rounded The furrows that separate the lobes are usually curved moderately incised and rarely completely cross the midline The eye ridges of Baltic holmiids are often wide with an ocular furrow inner band merging with L4 without axial furrow Laurentian holmiids Montezumaspis Palmetaspis Grandasinus Esmeraldina and Holmiella have unfurrowed ocular lobes separated from L4 by axial furrow The cephalon carries so called genal spines at the corner between the half circle front side margin and the back margin that is roughly perpendicular to the midline These spines extend back to at least the fourth thorax segment T4 counted front to back The back margin of the cephalon normally carries a node or spine or intergenal spine straight behind the point the eye ridge is furthest from the midline or even somewhat further out Back margin of cephalon inside the intergenal angle transverse or directed posteriorly The third thorax segment T3 is not larger than the neighboring segments and does not carry larger spines Anterior thoracic pleural spines weakly to strongly thornlike except in Kjerulfia and Grandinasus 6 References edit a b c d e f g h i j Lieberman B S 1999 Systematic Revision of the Olenelloidea Trilobita Cambrian PDF Bulletin of the Peabody Museum of Natural History 45 Archived from the original PDF on 2016 06 24 Retrieved 2019 05 09 Andalusiana Lotze 1958 trilobite The Paleobiology Database Callavia Matthew 1897 trilobite The Paleobiology Database Cambropallas Geyer 1993 trilobite The Paleobiology Database Elliptocephala Emmons 1844 The Paleobiology Database a b c d Hollingsworth J S 2006 Holmiidae Trilobita Olenellina of the Montezuman Stage Early Cambrian in Western Nevada Journal of Paleontology 80 2 309 332 doi 10 1666 0022 3360 2006 080 0309 htootm 2 0 co 2 JSTOR 4095128 S2CID 131683623 Ebbestad J O R Ahlberg P Hoyberget M 2003 Redescription of Holmia inusitata Trilobita from the Lower Cambrian of Scandinavia Palaeontology 46 5 1039 1054 Bibcode 2003Palgy 46 1039E doi 10 1111 1475 4983 00332 Iyouella Geyer and Palmer 1995 trilobite The Paleobiology Database Retrieved from https en wikipedia org w index php title Holmiidae amp oldid 1188114200, wikipedia, wiki, book, books, library,
