<?xml version="1.0" encoding="ISO-8859-1"?><article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<front>
<journal-meta>
<journal-id>0034-7744</journal-id>
<journal-title><![CDATA[Revista de Biología Tropical]]></journal-title>
<abbrev-journal-title><![CDATA[Rev. biol. trop]]></abbrev-journal-title>
<issn>0034-7744</issn>
<publisher>
<publisher-name><![CDATA[Universidad de Costa Rica]]></publisher-name>
</publisher>
</journal-meta>
<article-meta>
<article-id>S0034-77442021000500051</article-id>
<article-id pub-id-type="doi">10.15517/rbt.v69isuppl.1.46326</article-id>
<title-group>
<article-title xml:lang="en"><![CDATA[First record of Ubaghsicystis (Eocrinoidea - Echinodermata) from the Cambrian (Miaolingian, Wuliuan) of Sonora, Mexico: Biostratigraphical and paleoecological considerations]]></article-title>
<article-title xml:lang="es"><![CDATA[Primer registro de Ubaghsicystis (Eocrinoidea - Echinodermata) del Cámbrico (Miaolingio, Wuliuan) de Sonora, México: Consideraciones bioestratigráficas y paleoecológicas]]></article-title>
</title-group>
<contrib-group>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Buitrón-Sánchez]]></surname>
<given-names><![CDATA[Blanca-Estela]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Cuen-Romero]]></surname>
<given-names><![CDATA[Francisco-Javier]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Beresi]]></surname>
<given-names><![CDATA[Matilde-Sylvia]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Monreal]]></surname>
<given-names><![CDATA[Rogelio]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
</contrib-group>
<aff id="Af1">
<institution><![CDATA[,Universidad Nacional Autónoma de México  ]]></institution>
<addr-line><![CDATA[ ]]></addr-line>
<country>Mexico</country>
</aff>
<aff id="Af2">
<institution><![CDATA[,Universidad de Sonora  ]]></institution>
<addr-line><![CDATA[ Sonora]]></addr-line>
<country>Mexico</country>
</aff>
<aff id="Af3">
<institution><![CDATA[,Consejo Nacional de Investigaciones Científicas y Tecnológicas  ]]></institution>
<addr-line><![CDATA[ Mendoza]]></addr-line>
<country>Argentina</country>
</aff>
<pub-date pub-type="pub">
<day>00</day>
<month>03</month>
<year>2021</year>
</pub-date>
<pub-date pub-type="epub">
<day>00</day>
<month>03</month>
<year>2021</year>
</pub-date>
<volume>69</volume>
<fpage>51</fpage>
<lpage>61</lpage>
<copyright-statement/>
<copyright-year/>
<self-uri xlink:href="http://www.scielo.sa.cr/scielo.php?script=sci_arttext&amp;pid=S0034-77442021000500051&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.sa.cr/scielo.php?script=sci_abstract&amp;pid=S0034-77442021000500051&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.sa.cr/scielo.php?script=sci_pdf&amp;pid=S0034-77442021000500051&amp;lng=en&amp;nrm=iso"></self-uri><abstract abstract-type="short" xml:lang="en"><p><![CDATA[Abstract  Introduction:  The present work constitutes the first record of Ubaghsicystis Gil-Cid &amp; Domínguez-Alonso (Echinodermata-Eocrinoidea) in the El Gavilán Formation, exposed in the El Sahuaral Hill, a new Cambrian locality of central Sonora, Mexico. The El Gavilán Formation is a sedimentary sequence mainly made up of shale interbedded with limestone, with abundant invertebrate fossils, deposited in an open shelf marine environment.  Objective:  The main objective of this research work is to describe the species Ubaghsicystis cf. U. segurae for the first time in Mexico, in addition to biostratigraphic and paleoecological considerations.  Methods:  A composite stratigraphic section of the El Gavilán Fm. was measured in central Sonora, where samples corresponding to eocrinods were collected, the material was examined in the Microscope Leica MZ10.  Results:  The biotic association is composed of reticulosan sponges, chancelloriids (Chancelloria eros, Allonnia tintinopsis, Archiasterella sp.), hyolithids, brachiopods, trilobites (Quadragnostus depressa, Peronopsis sp., Tonkinella valida, and Elrathina sp.), and echinoderms (Ubaghsicystis cf. U. segurae). Regarding the age, the trilobite association establishes a chronostratigraphic position from the middle Cambrian (Miaolingian, Wuliuan), Altiocculus Subzone, Ehmaniella Zone. The material studied is constituted by isolated echinoderm plates, which probably represent various cycles of theca plates assigned to Ubaghsicystis cf. U. segurae. The genus Ubaghsicystis has been scarcely recorded in a few Cambrian regions (e.g., Burgess Shale in Canada and Los Barrios de Luna in Spain), so that the information about this taxon is limited.  Conclusions:  The Cambrian succession of Sonora, where Ubaghsicystis occurred, was part of the border from the Laurentia craton during this period, located near the Paleoequator during this period, where ideal conditions for increasing diversity and abundance of species were developed, including echinoderms.]]></p></abstract>
<abstract abstract-type="short" xml:lang="es"><p><![CDATA[Resumen  Introducción:  El presente trabajo constituye el primer registro en México de Ubaghsicystis Gil-Cid &amp; Domínguez-Alonso (Echinodermata-Eocrinoidea) procedente de la Formación El Gavilán, la cual aflora en el Cerro El Sahuaral, una nueva localidad del Cámbrico ubicada en la parte central del estado de Sonora, México. La Formación El Gavilán es una secuencia sedimentaria depositada en un ambiente marino de plataforma exterior, la cual consiste principalmente de lutita intercalada con caliza, conteniendo abundantes fósiles de invertebrados.  Objetivo:  El principal objetivo del presente trabajo de investigación es describir la especie Ubaghsicystis cf. U. segurae por primera vez para México, así como indicar las consideraciones bioestratigráficas y paleoecológicas.  Métodos:  Una sección estratigráfica compuesta fue medida para la Formación El Gavilán en Sonora central, donde muestras correspondientes a eocrinoides fueron colectadas, el material fue examinado en el Microscopio Leica MZ10.  Resultados:  La asociación biótica está conformada por esponjas reticulosas, chancellóridos (Chancelloria eros, Allonnia tintinopsis, Archiasterella sp.), hiolítidos, braquiópodos, trilobites (Quadragnostus depressa, Tonkinella valida, Elrathina sp.), y equinodermos (Ubaghsicystis cf. U. segurae). La asociación de trilobites confiere a estas rocas una edad del Cámbrico medio (Miaolingiano, Wuliuano), Subzona de Altiocculus, Zona de Ehmaniella. El material estudiado está constituido por placas aisladas y desarticuladas las cuales probablemente representen varios ciclos de placas de la teca, las cuales son asignadas a Ubaghsicystis cf. U. segurae. El género Ubaghsicystis ha sido documentado previamente en otras localidades del Cámbrico como Burgess Shale en Canadá y Los Barrios de Luna en España, para los cuales existen escasos registros.  Conclusiones:  La sucesión cámbrica de Sonora, donde ocurre Ubaghsicystis, formó parte del borde del cratón de Laurentia durante este período, el cual se localizaba cerca del Paleo Ecuador, donde se generaron las condiciones necesarias para una gran diversidad y abundancia de especies, incluyendo equinodermos.]]></p></abstract>
<kwd-group>
<kwd lng="en"><![CDATA[Eocrinoidea]]></kwd>
<kwd lng="en"><![CDATA[Cambrian]]></kwd>
<kwd lng="en"><![CDATA[biostratigraphy]]></kwd>
<kwd lng="en"><![CDATA[paleoecology]]></kwd>
<kwd lng="en"><![CDATA[Mexico]]></kwd>
<kwd lng="es"><![CDATA[Eocrinoidea]]></kwd>
<kwd lng="es"><![CDATA[Cámbrico]]></kwd>
<kwd lng="es"><![CDATA[bioestratigrafía]]></kwd>
<kwd lng="es"><![CDATA[paleoecología]]></kwd>
<kwd lng="es"><![CDATA[México]]></kwd>
</kwd-group>
</article-meta>
</front><back>
<ref-list>
<ref id="B1">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Almazán-Vázquez]]></surname>
<given-names><![CDATA[E.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[El Cámbrico-Ordovícico de Arivechi, en la región centro oriental del estado de Sonora]]></article-title>
<source><![CDATA[Revista del Instituto de Geología UNAM]]></source>
<year>1989</year>
<volume>8</volume>
<numero>1</numero>
<issue>1</issue>
<page-range>58-66</page-range></nlm-citation>
</ref>
<ref id="B2">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Beresi]]></surname>
<given-names><![CDATA[M.S.]]></given-names>
</name>
<name>
<surname><![CDATA[Buitrón-Sánchez]]></surname>
<given-names><![CDATA[B.]]></given-names>
</name>
<name>
<surname><![CDATA[Cuen-Romero]]></surname>
<given-names><![CDATA[F.J.]]></given-names>
</name>
<name>
<surname><![CDATA[Palafox]]></surname>
<given-names><![CDATA[J.J.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Escleritomos de Chancelloria eros y escleritos del Cámbrico medio (Serie 3, Piso 5) de Sonora central, México]]></article-title>
<source><![CDATA[Revista Mexicana de Ciencias Geológicas]]></source>
<year>2019</year>
<volume>36</volume>
<numero>1</numero>
<issue>1</issue>
<page-range>54-63</page-range></nlm-citation>
</ref>
<ref id="B3">
<nlm-citation citation-type="book">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Bruguière]]></surname>
<given-names><![CDATA[J.G.]]></given-names>
</name>
</person-group>
<source><![CDATA[Tableau Encyclopédique et Méthodique, au les Vers Infusoires, les Vers Intestines, les Vers Mollusques]]></source>
<year>1791</year>
<volume>7</volume>
<publisher-loc><![CDATA[Paris ]]></publisher-loc>
<publisher-name><![CDATA[Panckoucke]]></publisher-name>
</nlm-citation>
</ref>
<ref id="B4">
<nlm-citation citation-type="book">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Buitrón]]></surname>
<given-names><![CDATA[B.E.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Las rocas sedimentarias marinas del Paleozoico inferior de México y su contenido biótico]]></article-title>
<person-group person-group-type="editor">
<name>
<surname><![CDATA[Gutiérrez Marco]]></surname>
<given-names><![CDATA[J.C.]]></given-names>
</name>
</person-group>
<source><![CDATA[Paleozoico inferior de Ibero-América]]></source>
<year>1992</year>
<page-range>193-201</page-range><publisher-loc><![CDATA[Badajoz, Spain ]]></publisher-loc>
<publisher-name><![CDATA[Universidad de Extremadura]]></publisher-name>
</nlm-citation>
</ref>
<ref id="B5">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Buitrón-Sánchez]]></surname>
<given-names><![CDATA[B.]]></given-names>
</name>
<name>
<surname><![CDATA[Corona-González]]></surname>
<given-names><![CDATA[N.]]></given-names>
</name>
<name>
<surname><![CDATA[Cuen-Romero]]></surname>
<given-names><![CDATA[F.]]></given-names>
</name>
<name>
<surname><![CDATA[Palafox-Reyes]]></surname>
<given-names><![CDATA[J.J.]]></given-names>
</name>
<name>
<surname><![CDATA[Ramírez-Guerrero]]></surname>
<given-names><![CDATA[G.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Icnofósiles del Cámbrico Inferior de San José de Gracia, Sonora]]></article-title>
<source><![CDATA[Paleontología Mexicana]]></source>
<year>2016</year>
<volume>5</volume>
<numero>1</numero>
<issue>1</issue>
<page-range>33-40</page-range></nlm-citation>
</ref>
<ref id="B6">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Buitrón-Sánchez]]></surname>
<given-names><![CDATA[B.]]></given-names>
</name>
<name>
<surname><![CDATA[Cuen-Romero]]></surname>
<given-names><![CDATA[F.]]></given-names>
</name>
<name>
<surname><![CDATA[Huerta-Ruiz]]></surname>
<given-names><![CDATA[A.]]></given-names>
</name>
<name>
<surname><![CDATA[Montijo-González]]></surname>
<given-names><![CDATA[A.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Hiolítidos del Cámbrico (Hyolitha) de San José de Gracia, Sonora, México. Consideraciones estratigráficas y paleogeográficas]]></article-title>
<source><![CDATA[Paleontología Mexicana]]></source>
<year>2017</year>
<volume>6</volume>
<numero>1</numero>
<issue>1</issue>
<page-range>25-34</page-range></nlm-citation>
</ref>
<ref id="B7">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Buitrón-Sánchez]]></surname>
<given-names><![CDATA[B.]]></given-names>
</name>
<name>
<surname><![CDATA[Cuen-Romero]]></surname>
<given-names><![CDATA[F.J.]]></given-names>
</name>
<name>
<surname><![CDATA[Montijo-González]]></surname>
<given-names><![CDATA[A.]]></given-names>
</name>
<name>
<surname><![CDATA[Beresi]]></surname>
<given-names><![CDATA[S.M.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[El equinodermo Gogia granulosa (Echinodermata: Blastozoa) del Cámbrico temprano-medio en Sonora, México: paleoecología y paleogeografía]]></article-title>
<source><![CDATA[Revista de Biología Tropical]]></source>
<year>2017</year>
<volume>65</volume>
<numero>1</numero>
<issue>1</issue>
<page-range>160-7</page-range></nlm-citation>
</ref>
<ref id="B8">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Cooper]]></surname>
<given-names><![CDATA[G.A.]]></given-names>
</name>
<name>
<surname><![CDATA[Arellano]]></surname>
<given-names><![CDATA[A.R.V.]]></given-names>
</name>
<name>
<surname><![CDATA[Johnson]]></surname>
<given-names><![CDATA[J.H.]]></given-names>
</name>
<name>
<surname><![CDATA[Okulitch]]></surname>
<given-names><![CDATA[V.J.]]></given-names>
</name>
<name>
<surname><![CDATA[Stoyanow]]></surname>
<given-names><![CDATA[A.]]></given-names>
</name>
<name>
<surname><![CDATA[Lochman]]></surname>
<given-names><![CDATA[C.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Cambrian Stratigraphy and Paleontology near Caborca, northwestern Sonora, México]]></article-title>
<source><![CDATA[Smithsonian Miscellaneous Collections]]></source>
<year>1952</year>
<volume>119</volume>
<page-range>1-184</page-range></nlm-citation>
</ref>
<ref id="B9">
<nlm-citation citation-type="book">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Cooper]]></surname>
<given-names><![CDATA[G.A.]]></given-names>
</name>
<name>
<surname><![CDATA[Arellano]]></surname>
<given-names><![CDATA[A.R.V.]]></given-names>
</name>
<name>
<surname><![CDATA[Johnson]]></surname>
<given-names><![CDATA[J.H.]]></given-names>
</name>
<name>
<surname><![CDATA[Okulitch]]></surname>
<given-names><![CDATA[V.J.]]></given-names>
</name>
<name>
<surname><![CDATA[Stoyanow]]></surname>
<given-names><![CDATA[A.]]></given-names>
</name>
<name>
<surname><![CDATA[Lochman]]></surname>
<given-names><![CDATA[C.]]></given-names>
</name>
</person-group>
<source><![CDATA[Geología y Paleontología de la región de Caborca, norponiente de Sonora]]></source>
<year>1956</year>
<publisher-loc><![CDATA[Ciudad de México ]]></publisher-loc>
<publisher-name><![CDATA[Universidad Nacional Autónoma de México, Instituto de Geología]]></publisher-name>
</nlm-citation>
</ref>
<ref id="B10">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Cuen]]></surname>
<given-names><![CDATA[R.F.]]></given-names>
</name>
<name>
<surname><![CDATA[Beresi]]></surname>
<given-names><![CDATA[M.S.]]></given-names>
</name>
<name>
<surname><![CDATA[Montijo]]></surname>
<given-names><![CDATA[A.]]></given-names>
</name>
<name>
<surname><![CDATA[Buitrón]]></surname>
<given-names><![CDATA[B.E.]]></given-names>
</name>
<name>
<surname><![CDATA[Minjárez]]></surname>
<given-names><![CDATA[I.]]></given-names>
</name>
<name>
<surname><![CDATA[De la O.]]></surname>
<given-names><![CDATA[M.]]></given-names>
</name>
<name>
<surname><![CDATA[Palafox]]></surname>
<given-names><![CDATA[J.J.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Chancelloriia Walcott, 1920 y Reticulosa Reid, 1958 del Cámbrico medio de San José de Gracia, Sonora, México]]></article-title>
<source><![CDATA[Boletín de la Sociedad Geológica Mexicana]]></source>
<year>2013</year>
<volume>65</volume>
<page-range>581-90</page-range></nlm-citation>
</ref>
<ref id="B11">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Cuen-Romero]]></surname>
<given-names><![CDATA[F.J.]]></given-names>
</name>
<name>
<surname><![CDATA[Valdez-Holguín]]></surname>
<given-names><![CDATA[J.E.]]></given-names>
</name>
<name>
<surname><![CDATA[Buitrón]]></surname>
<given-names><![CDATA[B.E.]]></given-names>
</name>
<name>
<surname><![CDATA[Monreal]]></surname>
<given-names><![CDATA[R.]]></given-names>
</name>
<name>
<surname><![CDATA[Sundberg]]></surname>
<given-names><![CDATA[F.]]></given-names>
</name>
<name>
<surname><![CDATA[Montijo-González]]></surname>
<given-names><![CDATA[A.]]></given-names>
</name>
<name>
<surname><![CDATA[Minjarez-Sosa]]></surname>
<given-names><![CDATA[I.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Cambrian Stratigraphy of San José de Gracia, Sonora, Mexico: El Gavilán Formation, a new lithostratigraphic unit of middle Cambrian open shelf environment]]></article-title>
<source><![CDATA[Boletín de la Sociedad Geológica Mexicana]]></source>
<year>2016</year>
<volume>68</volume>
<numero>3</numero>
<issue>3</issue>
<page-range>429-41</page-range></nlm-citation>
</ref>
<ref id="B12">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Cuen-Romero]]></surname>
<given-names><![CDATA[F.J.]]></given-names>
</name>
<name>
<surname><![CDATA[Valdez-Holguín]]></surname>
<given-names><![CDATA[J.E.]]></given-names>
</name>
<name>
<surname><![CDATA[Buitrón-Sánchez]]></surname>
<given-names><![CDATA[B.E.]]></given-names>
</name>
<name>
<surname><![CDATA[Monreal]]></surname>
<given-names><![CDATA[R.]]></given-names>
</name>
<name>
<surname><![CDATA[Enríquez-Ocaña]]></surname>
<given-names><![CDATA[L.F.]]></given-names>
</name>
<name>
<surname><![CDATA[Aguirre-Hinojosa]]></surname>
<given-names><![CDATA[E.]]></given-names>
</name>
<name>
<surname><![CDATA[Palafox-Reyes]]></surname>
<given-names><![CDATA[J.J.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Trilobite-based biostratigraphy (Arthropoda-Trilobita) and related faunas of the Cambrian from Sonora, Mexico]]></article-title>
<source><![CDATA[Journal of South American Earth Sciences]]></source>
<year>2018</year>
<volume>83</volume>
<page-range>227-36</page-range></nlm-citation>
</ref>
<ref id="B13">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Cuen-Romero]]></surname>
<given-names><![CDATA[F.J.]]></given-names>
</name>
<name>
<surname><![CDATA[Valdez-Holguín]]></surname>
<given-names><![CDATA[J.E.]]></given-names>
</name>
<name>
<surname><![CDATA[Buitrón-Sánchez]]></surname>
<given-names><![CDATA[B.E.]]></given-names>
</name>
<name>
<surname><![CDATA[Monreal]]></surname>
<given-names><![CDATA[R.]]></given-names>
</name>
<name>
<surname><![CDATA[Enríquez-Ocaña]]></surname>
<given-names><![CDATA[L.F.]]></given-names>
</name>
<name>
<surname><![CDATA[Hinojosa]]></surname>
<given-names><![CDATA[E.A.]]></given-names>
</name>
<name>
<surname><![CDATA[Palafox Reyes]]></surname>
<given-names><![CDATA[J.J.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Paleoecology of Cambrian communities of central Sonora, Mexico: Paleoenvironmental and biostratigraphic considerations]]></article-title>
<source><![CDATA[Journal of South American Earth Sciences]]></source>
<year>2019</year>
<volume>92</volume>
<page-range>631-45</page-range></nlm-citation>
</ref>
<ref id="B14">
<nlm-citation citation-type="book">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Danzos-Acuña]]></surname>
<given-names><![CDATA[G.H.]]></given-names>
</name>
</person-group>
<source><![CDATA[Bioestratigrafía del Cámbrico del Cerro El Sahuaral, Sonora, México: Paleoecología y Paleogeografía: Sonora, México]]></source>
<year>2018</year>
<publisher-loc><![CDATA[Mexico ]]></publisher-loc>
<publisher-name><![CDATA[Universidad de Sonora]]></publisher-name>
</nlm-citation>
</ref>
<ref id="B15">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Gil Cid]]></surname>
<given-names><![CDATA[M.D.]]></given-names>
</name>
<name>
<surname><![CDATA[Domínguez Alonso]]></surname>
<given-names><![CDATA[P.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Ubaghsicystis segurae nov. gen. y sp., nuevo Eocrinoide (Echinodermata) del Cámbrico Medio del Norte de España]]></article-title>
<source><![CDATA[Coloquios de Paleontología]]></source>
<year>2002</year>
<volume>53</volume>
<page-range>21-32</page-range></nlm-citation>
</ref>
<ref id="B16">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[González-León]]></surname>
<given-names><![CDATA[C.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Estratigrafía del Paleozoico de la Sierra del Tule, Noroeste de Sonora]]></article-title>
<source><![CDATA[Revista del Instituto de Geología UNAM]]></source>
<year>1986</year>
<volume>6</volume>
<numero>2</numero>
<issue>2</issue>
<page-range>117-35</page-range></nlm-citation>
</ref>
<ref id="B17">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Jaekel]]></surname>
<given-names><![CDATA[O.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Phylogenie und System der Pelmatozoen]]></article-title>
<source><![CDATA[Paläontologische Zeitschrift]]></source>
<year>1918</year>
<volume>3</volume>
<numero>1</numero>
<issue>1</issue>
<page-range>1-128</page-range></nlm-citation>
</ref>
<ref id="B18">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Liñán]]></surname>
<given-names><![CDATA[E.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Trilobites]]></article-title>
<source><![CDATA[Boletín de la SEA]]></source>
<year>1996</year>
<volume>16</volume>
<page-range>45-56</page-range></nlm-citation>
</ref>
<ref id="B19">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Lochman]]></surname>
<given-names><![CDATA[C.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[New Cambrian Trilobite Genera from Northwest Sonora, Mexico]]></article-title>
<source><![CDATA[Journal of Paleontology]]></source>
<year>1948</year>
<volume>22</volume>
<numero>4</numero>
<issue>4</issue>
<page-range>451-64</page-range></nlm-citation>
</ref>
<ref id="B20">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[McMenamin]]></surname>
<given-names><![CDATA[M.A.S.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Lower Cambrian trilobites, zonation, and correlation of the Puerto Blanco Formation, Sonora, Mexico]]></article-title>
<source><![CDATA[Journal of Paleontology]]></source>
<year>1987</year>
<volume>61</volume>
<numero>4</numero>
<issue>4</issue>
<page-range>738-49</page-range></nlm-citation>
</ref>
<ref id="B21">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Nardin]]></surname>
<given-names><![CDATA[E.]]></given-names>
</name>
<name>
<surname><![CDATA[Almazán-Vázquez]]></surname>
<given-names><![CDATA[E.]]></given-names>
</name>
<name>
<surname><![CDATA[Buitrón-Sánchez]]></surname>
<given-names><![CDATA[B.E.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[First report of Gogia (Eocrinoidea-Echinodermata) from the Early-Middle Cambrian of Sonora (México), with biostratigraphical and paleoecological comments]]></article-title>
<source><![CDATA[Geobios]]></source>
<year>2009</year>
<volume>42</volume>
<page-range>233-42</page-range></nlm-citation>
</ref>
<ref id="B22">
<nlm-citation citation-type="book">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Noriega-Ruiz]]></surname>
<given-names><![CDATA[H.A.]]></given-names>
</name>
</person-group>
<source><![CDATA[Litofacies, microfacies y biofacies del Cámbrico del área El Sahuaral, Sonora central: consideraciones paleoecológicas y paleogeográficas]]></source>
<year>2019</year>
<publisher-loc><![CDATA[Mexico ]]></publisher-loc>
<publisher-name><![CDATA[Universidad de Sonora]]></publisher-name>
</nlm-citation>
</ref>
<ref id="B23">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Noriega-Ruiz]]></surname>
<given-names><![CDATA[H.A.]]></given-names>
</name>
<name>
<surname><![CDATA[Cuen-Romero]]></surname>
<given-names><![CDATA[F.J.]]></given-names>
</name>
<name>
<surname><![CDATA[Enríquez-Ocaña]]></surname>
<given-names><![CDATA[L.F.]]></given-names>
</name>
<name>
<surname><![CDATA[Sundberg]]></surname>
<given-names><![CDATA[F.A.]]></given-names>
</name>
<name>
<surname><![CDATA[Monreal]]></surname>
<given-names><![CDATA[R.]]></given-names>
</name>
<name>
<surname><![CDATA[Varela-Romero]]></surname>
<given-names><![CDATA[A.]]></given-names>
</name>
<name>
<surname><![CDATA[Palafox-Reyes]]></surname>
<given-names><![CDATA[J.J.]]></given-names>
</name>
<name>
<surname><![CDATA[Grijalva-Noriega]]></surname>
<given-names><![CDATA[F.J.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Cambrian stratigraphy (Series 2 to Miaolingian) of the El Sahuaral area in central Sonora, Mexico: Biostratigraphic implications]]></article-title>
<source><![CDATA[Journal of South American Earth Sciences]]></source>
<year>2020</year>
<volume>103</volume>
<numero>2020</numero>
<issue>2020</issue>
<page-range>102797</page-range></nlm-citation>
</ref>
<ref id="B24">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Rasetti]]></surname>
<given-names><![CDATA[F.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Middle Cambrian Stratigraphy and faunas of the Canadian Rocky Mountains]]></article-title>
<source><![CDATA[Smithsonian Miscellaneous Collections]]></source>
<year>1951</year>
<volume>116</volume>
<page-range>1-277</page-range></nlm-citation>
</ref>
<ref id="B25">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Robison]]></surname>
<given-names><![CDATA[R.A.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Middle Cambrian Eocrinoids from western North America]]></article-title>
<source><![CDATA[Journal of Paleontology]]></source>
<year>1976</year>
<volume>39</volume>
<numero>3</numero>
<issue>3</issue>
<page-range>355-64</page-range></nlm-citation>
</ref>
<ref id="B26">
<nlm-citation citation-type="book">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Sprinkle]]></surname>
<given-names><![CDATA[J.]]></given-names>
</name>
</person-group>
<source><![CDATA[Morphology and evolution of the blastozoan echinoderms]]></source>
<year>1973</year>
<page-range>283</page-range><publisher-loc><![CDATA[Cambridge ]]></publisher-loc>
<publisher-name><![CDATA[Harvard University Museum of Comparative Zoology]]></publisher-name>
</nlm-citation>
</ref>
<ref id="B27">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Stewart]]></surname>
<given-names><![CDATA[J.H.]]></given-names>
</name>
<name>
<surname><![CDATA[Amaya-Martínez]]></surname>
<given-names><![CDATA[R.]]></given-names>
</name>
<name>
<surname><![CDATA[Palmer]]></surname>
<given-names><![CDATA[A.R.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Neoproterozoic and Cambrian strata of Sonora, Mexico: Rodinian supercontinent to Laurentian Cordilleran margin]]></article-title>
<source><![CDATA[Special Papers-Geological Society of America]]></source>
<year>2002</year>
<volume>365</volume>
<page-range>5-48</page-range></nlm-citation>
</ref>
<ref id="B28">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Stewart]]></surname>
<given-names><![CDATA[J.H.]]></given-names>
</name>
<name>
<surname><![CDATA[McMenamin]]></surname>
<given-names><![CDATA[A.S.]]></given-names>
</name>
<name>
<surname><![CDATA[Morales-Ramirez]]></surname>
<given-names><![CDATA[J.M.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Upper Proterozoic and Cambrian Rocks in the Caborca Region, Sonora, México. Physical Stratigraphy, Biostratigraphy, Paleocurrent Studies and Regional Relations]]></article-title>
<source><![CDATA[U.S. Geological Survey Professional Paper]]></source>
<year>1984</year>
<volume>1309</volume>
<page-range>36</page-range></nlm-citation>
</ref>
<ref id="B29">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Sumrall]]></surname>
<given-names><![CDATA[C.D.]]></given-names>
</name>
<name>
<surname><![CDATA[Zamora]]></surname>
<given-names><![CDATA[S.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[A columnal-bearing eocrinoid from the Cambrian Burgess Shale (British Columbia, Canada)]]></article-title>
<source><![CDATA[Journal of Paleontology]]></source>
<year>2015</year>
<volume>89</volume>
<numero>2</numero>
<issue>2</issue>
<page-range>366-8</page-range></nlm-citation>
</ref>
<ref id="B30">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Sundberg]]></surname>
<given-names><![CDATA[F.A.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Corynexochida and Prychopariida (Trilobita, Arthropoda) of the Ehmaniella Biozone (Middle Cambrian), Utah and Nevada]]></article-title>
<source><![CDATA[Contributions in Science]]></source>
<year>1994</year>
<volume>446</volume>
<page-range>137</page-range></nlm-citation>
</ref>
<ref id="B31">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Vega-Granillo]]></surname>
<given-names><![CDATA[R.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Geología de la Sierra de Mazatán]]></article-title>
<source><![CDATA[Boletín del Departamento de Geología]]></source>
<year>1996</year>
<volume>13</volume>
<page-range>89-102</page-range></nlm-citation>
</ref>
<ref id="B32">
<nlm-citation citation-type="journal">
<person-group person-group-type="author">
<name>
<surname><![CDATA[Zamora]]></surname>
<given-names><![CDATA[S.]]></given-names>
</name>
<name>
<surname><![CDATA[Clausen]]></surname>
<given-names><![CDATA[S.]]></given-names>
</name>
<name>
<surname><![CDATA[Álvaro]]></surname>
<given-names><![CDATA[J.J.]]></given-names>
</name>
<name>
<surname><![CDATA[Smith]]></surname>
<given-names><![CDATA[A.B.]]></given-names>
</name>
</person-group>
<article-title xml:lang=""><![CDATA[Pelmatozoa echinoderms as colonizers of carbonate firmgrounds in mid-Cambrian high-energy environments]]></article-title>
<source><![CDATA[Palaios]]></source>
<year>2010</year>
<volume>25</volume>
<page-range>764-8</page-range></nlm-citation>
</ref>
</ref-list>
</back>
</article>
