Chiton Research Articles

POLYPLACOPHORA FROM THE MIOCENE OF NORTH ITALY. PART 2: CALLOCHITONIDAE, CHITONIDAE, LEPIDOCHITONIDAE, ACANTHOCHITONIDAE AND CRYPTOPLACIDAE

This study completes the description of the chiton fauna (Mollusca, Polyplacophora) from deposits of the Miocene marine sequence of North Italy, located in Piedmont and Emilia Romagna regions. This second and final part describes chitons belonging to five families: Callochitonidae, Chitonidae, Lepidochitonidae, Acanthochitonidae and Cryptoplacidae. Nineteen species were identified, of which two are described as new ( Chiton sulcomarginatus sp. n. and Craspedochiton brunettii sp. n.), and 17 were already known. Craspedochiton mutinocrassus is the new name attributed to the species previously known as Acanthochiton costatus or A. costatus var. mutinocrassa ; Chiton sulcomarginatus sp. n., Lepidochitona monterosatoi , L. pliocinerea , and Acanthochitona oblonga , previously known only up to Pliocene, are reported for the first time from the Miocene of Italy. The stratigraphic distribution of numerous species thought to first appear in the Late Miocene ( Callochiton doriae , Chiton olivaceus , C. corallinus , Acanthochitona fascicularis , A. crinita , and Craspedochiton altavillensis ) is here extended to the Early Miocene. The distribution of Cryptoplax weinlandi is extended to the Middle Miocene (Serravallian). In total 35 chiton species (with 3.003 valves) were identified in the Italian Miocene (including both parts of this series). Ten species became extinct at the end of the Miocene, six in the Pliocene, two in the Pleistocene, and 17 are extant. Of the extant species nine occur both in the Atlantic and Mediterranean, two exclusively in the Atlantic and six only in the Mediterranean. The number of species reported from the Torino Hill assemblages (Burdigalian?) is increased from three listed by Sacco (1897) to nine. Thirty-four of the 35 species (excluding only Lepidopleurus benoisti ) occur in the Tortonian-Messinian Po Basin. Thirteen (37%) of the species are also found in the Miocene Paratethys (Austria, Poland, Czech Republic, Hungary, Romania and Ukraine), which can be explained by connections between the Proto-Mediterranean and Paratethys during the Miocene.

POLYPLACOPHORA FROM THE MIOCENE OF NORTH ITALY. PART 1: LEPTOCHITONIDAE, HANLEYIDAE, ISCHNOCHITONIDAE AND CALLISTOPLACIDAE

This study describes the chiton fauna (Mollusca, Polyplacophora) from deposits of the Miocene marine sequence of North Italy, located in Piedmont and Emilia Romagna regions. This first part of the work describes the chitons pertaining to four families: Leptochitonidae, Hanleyidae, Ischnochitonidae and Callistoplacidae. The studied fossils consist of 377 valves from 13 sites (Sciolze, Valle Ceppi, Rocco di Passerano, Albugnano, Monchio di Sarzano Casina, Villa Monti, Rio di Bocca d’Asino, Sant’Agata Fossili, Vargo, Vigoleno, Montegibbio, Borelli, and Moncucco Torinese) ranging from the Early Miocene (Burdigalian) to the Late Miocene (Messinian). We identified 16 species, 12 of which were already known, two are identified only at generic level ( Stenosemus sp. A & sp. B), and two are described as new: Parachiton statianus sp. n., and Callistochiton borellianus sp. n. Some species found are particularly noteworthy; Lepidopleurus benoisti is the new name attributed to the species previously known as Middendorffia subcajetana or Gymnoplax orbignyi , based on the study of the type material; Leptochiton salicensis , previously known only from the Early Pleistocene of Salice (Messina, Sicily); Hanleya mediterranea is reported for the first time from the Miocene of Italy; Ischnochiton ligusticus , previously known only from the Early Pliocene of Western Liguria; the distribution of Stenoplax paviai , recently described from the Late Miocene (Rio di Bocca d’Asino), is extended to the Early Miocene (Langhian). A complete discussion on the chiton fauna from the North Italian Miocene, consisting of all the species treated in both parts, will be given in the second part of this work.

Respuesta del carnívoro Plicopurpura pansa (mollusca: gastropoda) y el herbívoro Chiton articulatus (mollusca: polyplacophora) a factores ambientales en Acapulco, México

El gasterópodo Plicopurpura pansa y el poliplacóforo Chiton articulatus, cohabitan en la zona intermareal rocosa del Pacífico tropical Mexicano. Se ha reportado que P. pansa es un depredador de C. articulatus, y que ambas son especies abundantes y dominantes en la costa rocosa de Acapulco, Guerrero, México. El presente estudio analizó los patrones de respuesta de la densidad relativa y longitudes de ambas especies a cinco factores ambientales registrados en cuatro localidades rocosas de esta región. Durante octubre y diciembre de 2010, así como febrero y abril de 2011, se realizaron muestreos sistemáticos. Los sitios de estudio difirieron en la complejidad del sustrato y oleaje. Se registró el número de organismos por metro cuadrado y su longitud total, así como la temperatura del mar, salinidad y clorofila-α. Las densidades relativas de cada especie variaron entre los sitios de estudio y en todos los casos fueron mayores a 1.0 org/m2. Se observó una relación de la longitud del poliplacóforo con la temperatura del mar, salinidad y clorofila-α; una relación de la abundancia y longitud del gasterópodo con la complejidad del sustrato; y por último, una mayor abundancia del poliplacóforo en zonas de alto oleaje. También, se observaron comportamientos diferenciados de las especies en función de las características de los sitios rocosos y de los factores ambientales. La abundancia y longitud del carnívoro P. pansa estuvieron estrechamente relacionadas con el tipo de sustrato rocoso. En el caso del poliplacóforo C. articulatus, a través del tiempo, su longitud se asocia con parámetros físico-químicos del mar; mientras que a nivel espacial, sus abundancias se relacionan con el tipo de sustrato y la intensidad de oleaje

ACUTE TOXICITIES OF CRUDE OILS AND OIL-DISPERSANT MIXTURES TO RED SEA FISHES AND INVERTEBRATES

ABSTRACT Crude oil from fields in the Persian Gulf and in the Sinai plus a chemical oil dispersant were tested, using static bioassay procedures, for toxicity to adults or juveniles of ten marine species: Heteroxenia fuscescens, a soft coral; Nerita forskali and Drupa granulata, gastropod molluscs; Mytilus variabilis, a mussel; Acanthopleura haddoni, a chiton (mollusc); Echinometra mathaei, sea urchin; Calcinus latens, a hermit crab; Palaemon pacificus, a shrimp; Parupeneus barberinus, goatfish; and Siganus rivulatus, rabbitfish. Concentrations fatal to 50% of individual test species in 168 hours, LC-50 (168 h), ranged from 0.74 to more than 30.0 ml/liter for Persian Gulf crude, from 14.5 to more than 30.0 ml/liter for Sinai crude, and from 0.006 to 0.064 ml/liter for the dispersant. In general, fishes and crustaceans were the most sensitive groups assayed and molluscs the most resistant LC-50 (168 h) values for oil-dispersant mixtures of 10 parts oil to 1 part dispersant (v/v) for selected species ranged...

NOTES ON FOSSIL CHITONS. 5. POLYPLACOPHORA FROM THE PLIOCENE OF WESTERN LIGURIA, NORTHWEST ITALY

This study describes the chiton fauna (Mollusca, Polyplacophora) from deposits of the Pliocene marine sequence of Western Liguria in northwestern Italy between Genova (Genoa) and Ventimiglia. The studied fossils consist of 9,657 valves from nine sites (Bussana, Rio Sant'Antonino, Garlenda, Salea, Caranchi, Rio Torsero, Zinola, Sestri Ponente, and Borzoli; see Fig. 1) taken from the lower clayey formation named Argille di Ortovero (Ortovero Clay). From these we identified 31 species, 22 of which were already known, 5 are identified only at generic level, and four are described as new: Leptochiton josei sp. n., Ischnochiton ligusticus sp. n., Connexochiton roccai sp. n., and Lepidochitona pliocinerea sp. n. Only three species ( Lepidopleurus cajetanus, Chiton corallinus and Acanthochitona fascicularis ) occur in all the studied sites but, even so, it is difficult to evaluate their relative prevalence. Ch. corallinus and Lepidop. cajetanus are most common, representing 46% and 31% respectively of the total valves found. Some species found are particularly noteworthy; Lept. alveolus previously not known as a fossil, except a dubiously identified record from the Eocene/Oligocene of Washington; Lept. bedullii and I. martinelli are known only from few Pliocene localities. Four species are described as new, and this increases the number of Mediterranean Pliocene determined species known to 37. Connexochiton roccai sp. n. represent the first report of Connexochiton as a fossil. Seventeen (55%) of the species found are still living in the Mediterranean Sea and 13 of these also occur in the eastern Atlantic. Only one species, Lept. alveolus , occurs as a living species in the Atlantic but is absent from the Mediterranean Sea. Five determined species are known only from Mediterranean Pliocene, and 12 are recorded for the first time from the Ligurian Pliocene. The analysis of the Ligurian samples suggests a shallow water depositional environment, possibly from lower infralittoral to circalittoral depth, and suggests a mixture of faunal elements from different depths and environments.

Following biomineral deposition fronts in marine chiton teeth by Raman spectroscopy

Following biomineral deposition fronts in marine chiton teeth by Raman spectroscopy

Oxygen consumption in six species of chitons in relation to their position on the shore

Abstract Aerial and aquatic oxygen consumption rates have been measured in six species of intertidal chi tons with respect to zonation, size and oxygen concentration of the external medium. Those species occurring highest on the shore were found to have a lower rate of aquatic oxygen consumption than those ~i'eeies occurring lowest on the shore, with mid-shore species showing intermediate rates. Aerial oxygen consumption rates were similar in most species and were not strictly correlated with their position on the shore. High shore chitons had higher or equal rates in air than in water, while low shore species had higher aquatic than aerial rates. It was also found that the six species could be grouped with respect to their oxyregulatory capabilities when exposed to declining oxygen tensions and these groups could be correlated with the species intertidal zonation: high shore species show a high degree of oxygen independence, mid-shore species a moderate degree and low shore animals little or no regulator...

The aesthetes of chitons

The aesthetes of chitons

Upper Wolfcampian (?) mollusca from the Arrow Canyon Range, Clark County, Nevada

An abundant and diverse silicified fauna comprised mostly of gastropods, but including pelecypods, scaphopods, chitons, small orthoconic nautiloids, sponges, ostracodes, a trilobite species, and foraminifers, occurs in association with the alga Mizzia in a structurally isolated portion of the upper Bird Spring Group (BSe Unit). At least three gastropod species, Amaurotoma zappa, Glyptospira arelela, and Anomphalus jaggerius, are new. The assemblage resembles, in some respects, that described by Chronic (1952) from the Kaibab Formation (Leonardian-Guadalupian) of Arizona as well as undescribed assemblages from the Loray Formation (upper Leonardian) of eastern Nevada and the Bird Spring Group (middle Wolfcampian ?) of the Providence Mountains in southwestern Nevada. The fauna is tentatively assigned an uppermost Wolfcampian age on the basis of Schwagerina cf. S. crassitectoria Dunbar & Skinner, which occurs several hundred feet above the mollusk-bearing bed, as well as on the occurrence of Mizzia cf. M. yabei (Karpinski), previously reported from Middle to Late Permian rocks. Color markings are preserved on some of the gastropods, a chiton and a nautiloid.

An Observation on the "Cluster-Formation" of the Sperms of Chiton

Previous article FreeShorter Articles and DiscussionAn Observation on the "Cluster-Formation" of the Sperms of ChitonW. J. CrozierW. J. Crozier Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by The American Naturalist Volume 56, Number 646Sep. - Oct., 1922 Published for The American Society of Naturalists Article DOIhttps://doi.org/10.1086/279892 Views: 39Total views on this site Citations: 5Citations are reported from Crossref PDF download Crossref reports the following articles citing this article:John S. Pearse POLYPLACOPHORA, (Jan 1979): 27–85.https://doi.org/10.1016/B978-0-12-282505-7.50009-9A. C. GIESE, J. S. TUCKER, and R. A. BOOLOOTIAN ANNUAL REPRODUCTIVE CYCLES OF THE CHITONS, KATHERINA TUNICATA AND MOPALIA HINDSII, The Biological Bulletin 117, no.11 (Sep 2016): 81–88.https://doi.org/10.2307/1539040T. M. Woodard The function of the apyrene spermatozoa of Goniobasis laqueata (say) I. The behavior of the apyrene and eupyrene spermatozoa under natural and artificial conditions, Journal of Experimental Zoology 85, no.11 (Oct 1940): 103–125.https://doi.org/10.1002/jez.1400850106WALTER E. SOUTHWICK THE "AGGLUTINATION" PHENOMENON WITH SPERMATOZOA OF CHITON TUBERCULATUS, The Biological Bulletin 77, no.22 (Sep 2016): 157–165.https://doi.org/10.2307/1537918C. Amirthalingam On Lunar Periodicity in Reproduction of Pecten opercularis near Plymouth in 1927–28, Journal of the Marine Biological Association of the United Kingdom 15, no.22 (May 2009): 605–641.https://doi.org/10.1017/S0025315400009565

"Homing" Behavior in Chiton

"Homing" Behavior in Chiton

Sex-Correlated Coloration in Chiton tuberculatus

Previous articleNext article FreeShorter Articles and DiscussionSex-Correlated Coloration in Chiton tuberculatusW. J. CrozierW. J. Crozier Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by The American Naturalist Volume 54, Number 630Jan. - Feb., 1920 Published for The American Society of Naturalists Article DOIhttps://doi.org/10.1086/279740 Views: 113Total views on this site Citations: 4Citations are reported from Crossref PDF download Crossref reports the following articles citing this article:John S. Pearse POLYPLACOPHORA, (Jan 1979): 27–85.https://doi.org/10.1016/B978-0-12-282505-7.50009-9H. Erhard Farbwechsel und Pigmentierungen und ihre Bedeutung, (Jan 1929): 193–263.https://doi.org/10.1007/978-3-642-91032-6_4 Muscular exercise, lactic acid, and the supply and utilisation of oxygen.—Parts ӏ-ӏӏӏ, Proceedings of the Royal Society of London. Series B, Containing Papers of a Biological Character 96, no.679679 (Jan 1997): 438–475.https://doi.org/10.1098/rspb.1924.0037 W. J. Crozier An Observation on the "Cluster-Formation" of the Sperms of Chiton, The American Naturalist 56, no.646646 (Sep 2015): 478–480.https://doi.org/10.1086/279892

Coalescence of the Shell-Plates in Chiton

Coalescence of the Shell-Plates in Chiton

Growth of Chiton Tuberculatus in Different Environments

Growth of Chiton Tuberculatus in Different Environments

XXXIX.—On the development of the Chitons

XXXIX.—<i>On the development of the</i> Chitons