Speciesbox taxon Turbonilla laminata image Turbonilla laminata 001.png image caption Drawing of a gastropod shell shell of Turbonilla laminata authority Carpenter, 1864 synonyms ref synonyms Turbonilla laminata is a species of sea snail , a marine ocean marine gastropod mollusk in the family biology family Pyramidellidae , the pyrams and their allies. ref name WoRMS Rosenberg, G. 2011 . Turbonilla laminata Carpenter, 1864 . Accessed through World Register of Marine Species at http www.marinespecies.org aphia.php?p taxdetails&id 581342 on 2012 03 01 ref ref Turgeon, D. Quinn, J.F. Bogan, A.E. Coan, E.V. Hochberg, F.G. Lyons, W.G. Mikkelsen, P.M. Neves, R.J. Roper, C.F.E. Rosenberg, G. Roth, B. Scheltema, A. Thompson, F.G. Vecchione, M. Williams, J.D. 1998 . Common and scientific names of aquatic invertebrates from the United States and Canada mollusks. 2nd ed. American Fisheries Society Special Publication, 26. American Fisheries Society Bethesda, MD USA . ISBN 1 888569 01 8. IX, 526 cd rom pp. ref Description The shell has the shape of an elongate cone. Its length measures 6.25 mm. Its color is yellowish or fulvous, more or less distinctly narrowly fasciate with lighter color on the Spire mollusc spire , and bifasciate on the body whorl . The protoconch contains two Whorl mollusc whorl s. The eight whorls of the teleoconch are convex. They contain a deep suture. They are longitudinally and spirally ribbed. The interstices of the decussations appear as pitted. On the body whorl the longitudinal Sculpture mollusc sculpture becomes evanescent below the periphery ref name Tryon http www.archive.org stream manualconch08tryorich page n5 mode 2up G.W. Tryon 1886 , Manual of Conchology vol. VIII p. 338 ref Distribution This species occurs in the Pacific Ocean off San Diego , California. References reflist External links TaxonIds worms 581342 itis ncbi eol http www.marinespecies.org aphia.php?p taxdetails&id 581342 To World Register of Marine Species Category Pyramidellidae ... more details
italic title Taxobox name Bullina roseana image image caption status regnum Animal ia phylum Mollusk Mollusca classis Gastropoda unranked superfamilia clade Heterobranchia br informal group Lower Heterobranchia superfamilia Acteonoidea familia Bullinidae genus Bullina species B. roseana binomial Bullina roseana binomial authority Rudman , 1971 Bullina roseana is a species of small sea snail , a bubble snail, a marine ocean marine gastropod mollusc in the family Bullinidae , one of the families of bubble snails. Description The gastropod shell shell of this species is globose , ovate , and has an Umbilicus mollusc umbilicus . The shell color is white with 3 pink lines running along the surface of the body whorl, the middle line being twice the width of the other two. The shell also has 7 pinkish axial lines, but they are more diffuse. The spire is relatively low, approximately 1 9 of the shell height, with a large protoconch , and rounded whorl s. The shell sculpture consists of smooth spiral ridges separated by narrow punctate grooves. The ridges are approximately 1 3 to 1 25 of the width of the whorl. The shell has a large aperture which narrows at the upper end and also slightly at the lower end. The outer lip is thin and is joined by the body whorl above the upper spiral line. The shell has a channelled Suture anatomy suture and a white, straight, and broad columella gastropod columella which is slightly truncated at the base. There is a calcified layer over the lower half of the shell aperture which is formed by the inner lip. ref name seaslugforum http www.seaslugforum.net bullrose.htm Description and headshield ref Headshield This species has a headshield , which has a brown coloured oral tube that shows through the body wall. The headshield has permanent funnel on each side, which leads water down over the chemosensory Hancock s organ which is within the groove, between the headshield and the foot. ref name seaslugforum References Reflist Category Bullinidae ... more details
, semitransparent, pale cinnamon pink in colour with pearly lustre. The shell has 8.5 whorl mollusc whorls ... spiral keels are dividing the surface of whorl into three parts with unequal interval the uppermost ... and many exceedingly fine spiral lines near the body whorl . The lowest one is the narrowest of them all. The lowest spiral keel is concealed with succeeding whorl. The number of beads on the upper most spiral keel is ca 165 177 on the last whorl, ca 130 on penultimate whorl, ca 80 on the sixth whorl, ca 50 on the fifth whorl, ca 42 on the fourth whorl, ca 28 on the third whorl and ca 19 on the second whorl. ref name Otuka 1939 The base is sculptured with about 40 spiral threads. The inner ... more details
Image Alcithoe arabica smooth form, underside view .JPG thumb The aperture mollusc aperture of Alcithoe swainsoni shows five plaits on the Collumella mollusk columella , four strong and one weak A plait is an anatomical feature which is present the gastropod shell shells of some snail s, or gastropod s. This Sculpture mollusc sculpture occurs often in the shells of marine ocean marine gastropod mollusk s in the clade Neogastropoda , but it is also found in some pulmonate land snails. Plaits are folds on the Collumella mollusk columella also known as the pillar or axis at the center of the shell. The columella meaning little column is the central structure around which the whorl mollusc whorl s of a coiled gastropod shell are coiled. The presence or absence of plaits, and the number of plaits, are characteristics used in the description of many gastropod molluscs, often enabling similar species to be separated and identified correctly. References reflist Arthur William Baden Powell Powell A W B , New Zealand Mollusca , HarperCollins William Collins Publishers Ltd , Auckland, New Zealand 1979 ISBN 0 00 216906 1 Category Mollusc anatomy Category Gastropods ... more details
italic title Taxobox name Beyrichites status fossil fossil range M Triassic regnum Animalia phylum Mollusca classis Cephalopoda subclassis Ammonoidea ordo Ceratitida superfamilia Ceratitaceae familia Beyrichitidae genus Beyrichites genus authority Waagen, 1895 Beyrichites is an extinct genus in the Ammonoidea ammonoid cephalopod, order Ceratitida from the Lower and Middle Triassic of southern Europe, Asia, and western North America. Beyrichites has an involute, discoidal shell with a narrowly arched venter and signoidal ribbing that tends to disappear on the outer whorl. The suture is subammonitic, meaning the saddles are serrate as well as the lobs. Two subgenera are recognized B. Beyrichites from the Lower and Middle Triassic, which has no tubercles, and B. Gangadharites from the Middle Triassic of the Himalaya which has tbercles on the whorl sides. small References small Treatise on Invertebrate Paleontology, Part L Ch. Mesozoic Ammonoidea. Geological Soc of America and U Kansas Press, R.C Moore ed Category Ceratitida Ammonite stub ... more details
Other uses Lemma disambiguation Lemma Image En Anatomia.png Parts of a single grass spikelet, consisting of two glumes, four fertile florets, with one additional central floret that may or may not be sterile thumb 200px right Lemma is a plant morphology phytomorphological term used in botany referring to a part of the spikelet of grass es Poaceae . It is the lowermost of two chaff like bract s enclosing the grass floret . It often bears a long bristle called an awn botany awn , and may be similar in form to the glume s chaffy bracts at the base of each spikelet. It is usually interpreted as a bract but it has also been interpreted as one remnant the abaxial of the three members of outer perianth Whorl botany whorl the palea botany palea may represent the other two members, having been joined together . A lemma s shape, their number of veins, whether they are awned or not, and the presence or absence of hairs are particularly important phenotypic trait character s in grass taxonomy . DEFAULTSORT Lemma Botany Category Plant morphology botany stub id Lemma botani ja fi Kale ... more details
italic title Taxobox name Cyathea nigrolineata regnum Plant ae divisio Pteridophyta classis Pteridopsida ordo Cyatheales familia Cyatheaceae genus Cyathea sectio Cyathea sect. Alsophila Alsophila species C. nigrolineata binomial Cyathea nigrolineata binomial authority Richard Eric Holttum Holttum , 1962 Cyathea nigrolineata is a species of tree fern in the family Cyatheaceae . Its trunk is approximately 10 meters tall. It has fronds that are 2 to 3 meters in length and bipinnate bi or tripinnate . The fronds are placed in groups of 5 to 8 per wikt whorl whorl . The Stipe botany stipe is scaly. It occurs in Eastern New Guinea forests at about 2000 meters. References cite book author Braggins, John E. coauthors Large, Mark F. year 2004 title Tree Ferns publisher Timber Press isbn 0 88192 630 2 page 231 Category Cyathea nigrolineata Category Fern species ... more details
automatic taxobox fossil range Fossil range Pennsylvanian Late Permian authority Miller, et al, 1947 Condraoceras is a Liroceratidae liroceratid from the Pennsylvanian of North America and Lower Permian of Europe with a compressed, involute, nautiliconic shell subcircular whorl section small umbilicus with a rounded shoulder suture with shallow ventral and lateral lobes and narrow subcentral siphuncle. Liroceras , from the same time and type of the family, differs in having a reniform whorl section and essentially straight sutures at maturity. Peripetoceras , another related genus, has a flattened venter, slight ventral and lateral lobes in the suture, and a siphuncle offset dorsally from the center. References Bernhard Kummel, 1964. Nautiloidea Nautilida Treatise on Invertebrate Paleontology , Part K. Geol Soc of America and Univ of Kansas press, R.C. Moore ed Liroceratidae K444 K447. Category Nautiloids Nautiloidea stub Paleo cephalopod stub ... more details
italic title Taxobox name Liroceras fossil range Mississippian L Carboniferous Carb Permian image regnum Animalia phylum Mollusca classis Cephalopoda subclassis Nautiloidea ordo Nautilida superfamilia Clydonautilaceae familia Liroceratidae genus Liroceras genus authority Teichert, 1940 Liroceras is the type genus of the Clydonautilaceae clydonautiliacean family, Liroceratidae , and is characterized by a rapidly expanding, subglobular, nautiliconic shell with a reniform whorl section, small umbilicus, essentially straight sutures, and a siphuncle with a variable but not marginal position. Liroceras has a range from the Mississippian to the Permian, longest of the Liroceratidae. It has been found the North America, Europe, China and the East Indies. Condraoceras differs in having a circular cross section and shallow ventral and lateral lobes. Bistrialites also has a reniform whorl section but differs in ahving a large funnel shaped umbilicus. References Bernhard Kummel, 1964. Nautiloidea Nautilida Treatise on Invertebrate Paleontology , Part K. Geol Soc of America and Univ of Kansas press, R.C. Moore ed Liroceratidae K444 K447. Category Nautiloids ... more details
italic title Taxobox name Holconautilus fossil range Upper Triassic image regnum Animalia phylum Mollusca classis Cephalopoda subclassis Nautiloidea ordo Nautilida superfamilia Tainocerataceae familia Tainoceratidae genus Holconautilus genus authority Mojsisovics, 1902 Holconautilus is a Nautiloidea Nautiloid genus from the family Tainoceratidae and order Nautilida , named by Mojsisovics, 1902, and known from Upper Triassic sediments in Europe and E Indies Timor . Its shell, evolute, discoidal, with simple coarse lateral ribbing whorl section, subrectagular with a broadly arched venter. Holconautilus somewhat resembles the Permo Triassic Pleuronautilus except its suture has ventral saddles instead of ventral lobes and lateral ribs are continuous. Anoploceras , from the same time and place as Holconautilus is also similar except for having a wider whorl section and a venter that is slightly concave. References Bernhard Kummel, 1964. Nautiloidea Nautilida. Treatise on Invertebrate Paleontology, Part K. Geological Soc. of America and University of Kansas press. Teichert and Moore eds Category Nautiloids Nautiloidea stub paleo cephalopod stub ... more details
Taxobox name Tetragonoceratidae fossil range M Devonian image regnum Animal ia phylum Mollusca classis Cephalopoda subclassis Nautiloidea ordo Nautilida superfamilia Tainocerataceae familia Tetragonoceratidae familia authority Rousseau Flower Flower , 1945 The Tetragonoceratidae is a small family of Nautilida nautilitids constituting a part of the superfamily Tainocerataceae in which shells are coiled with a generally quadrate whorl section. Coiling is either gyroconic or evoluute with a slight dorsal impression. Flanks diverge from the umbilical to the ventral shoulders so as to make the whorl sections widest close to the venter. Nodes made develop on the flanks and shoulders. The siphuncle is tubular, typically found near the venter. Sutures are with lateral lobes and may possess dorsal and ventral lobes as well. The Tetragonoceratidae, which is an early offshoot of the Rutoceratidae , contains three genera as of 1964 , all confined to the Middle Devonian Tetragonoceras , Nassauoceras , and Wellsoceras . References Bernhard Kummel, 1964. Nautiloidea Nautilida. Treatise on Invertebrate Paleonology, Part K. R.C. Moore and Curt Teichert eds. Geological Society of America. Category Nautiloids paleo cephalopod stub ... more details
italic title Taxobox name Nassauoceras fossil range Midlle Devonian image regnum Animal ia phylum Mollusca classis Cephalopoda subclassis Nautiloidea ordo Nautilida superfamilia Tainocerataceae familia Tetragonoceratidae genus Nassauoceras genus authority Miller, 1932 Nassauoceras is a Tetragonoceratidae tetragonoceratid nautiloid from the Middle Devonian of Europe , the shell of which is evolute with a wide, deep umbilucus, slight dorsal impression, low arched venter, rounded ventral shoulders, and flanks that converge dorsally so as to produce a subtrigonal whorl section. Nodes are present on the ventral shoulders. Sutures have shallow ventral and lateral lobes. The siphuncle is near the ventral margin. Nassauoceras differs from Tetragonoceras in that the latter is gyroconic with a subquadrate whorl section and angular ventral shoulders, but is somewhat similar to Wellsoceras in which whorls are in contact in the early growth stages and shoulders are also rounded. References Bernhard Kummel, 1964. Nautiloidea Nautilida Treatise on Invertebrate Paleontology, Part L. R.C. Moore & Curt Teichert, eds. Geological Society of America, pub 1964. Category Nautiloids paleo cephalopod stub ... more details
ridges, the posterior one is fainter and placed in advance of the middle of the whorl. There is a slight ... as wide as the body whorl to the left of it, pointed behind, rounded and slightly oblique in front ... of the last whorl is 3.0 mm. ref name Dall The maximum recorded gastropod shell shell length ... more details
A cyclic flower is a flower type formed out of a series of Whorl botany whorls ref name Swartz cite book page 136 title Collegiate Dictionary of Botany last Swartz first Delbert publisher The Ronald Press Company location New York year 1971 ref sets of identical organs attached around the axis at the same point. Most flowers consist of a single whorl of sepal s termed a Calyx botany calyx a single whorl of petal s termed a corolla flower corolla one or more whorls of stamen s together termed the androecium and a single whorl of carpel s termed the gynoecium . This is a cyclic arrangement. Some flowers contain flower parts with a spiral arrangement. Such flowers are not cyclic. However in the common case of spirally arranged sepals on an otherwise cyclic flower, the term hemicyclic may be used ref name Jackson cite book page 174 title A Glossary of Botanic Terms with their Derivation and Accent last Jackson first Benjamin Daydon edition fourth publisher Gerald Duckworth & Co. Ltd. location London year 1928 url http www.archive.org details glossaryofbotani1928jack ref . The suffix cyclic is used to denote the number of number of whorls contained within a flower. The most common case is the pentacyclic flower, which contains five whorls ref cite book page 271 title A Glossary of Botanic Terms with their Derivation and Accent last Jackson first Benjamin Daydon edition fourth publisher Gerald Duckworth & Co. Ltd. location London year 1928 url http www.archive.org details glossaryofbotani1928jack ref a calyx, a corolla, two whorls of stamens, and a single whorl of carpels. Another common case is the tetracyclic flower, which contains only one whorl of stamens, and therefore only four whorls in total. Tricyclic flowers also occur, generally where there is a single undifferentiated Petal perianth . Flowers with more than five whorls are also not uncommon. The greatest variation occurs in the calyx and the androecium. Calyces of up to nine whorls have been recorded, and up to 12 ... more details
Speciesbox taxon Turbonilla mexicana image Turbonilla mexicana 001.png image caption Drawing of a gastropod shell shell of Turbonilla mexicana authority Dall & Bartsch, 1909 ref name Dall synonyms ref synonyms Turbonilla Longchaeus mexicana Dall & Bartsch, 1909 Turbonilla mexicana is a species of sea snail , a marine ocean marine gastropod mollusk in the family biology family Pyramidellidae , the pyrams and their allies. ref name WoRMS WoRMS 2011 . Turbonilla mexicana Dall & Bartsch, 1909. Accessed through World Register of Marine Species at http www.marinespecies.org aphia.php?p taxdetails&id 576069 on 2012 03 01 ref ref Keen M. 1971 . Sea shells of Tropical West America. Marine mollusks from Baja California to Per . 2nd edit. . Stanford University Press pp. 1064 ref Description The robust, dull brown shell is large and broadly conic, dull brown. The Whorl mollusc whorl s of the protoconch are decollated and propably the first whorl of teleoconch is missing from the type specimen All but the last whorl of the teleoconch are flattened, flatly shouldered and crenulated at the summit. The body whorl is inflated and well rounded. The periphery of the body whorl is marked by a strong sulcus. The Suture anatomy suture s are chamieled. The entire surface of the Spire mollusc spire and the base is marked by lines of growth, which are quite prominent on the last turn. The base is inflated, strongly rounded, with a slender fasciole at the insertion of the Columella gastropod columella . The Aperture mollusc aperture is oval. The posterior angle is acute. The shell is slightly channeled anteriorly. The Lip gastropod outer lip is thin, with a white band at the periphery. The remainder is brown with darker colored lines, reinforced deeply within by five spiral cords, two of which are posterior and three anterior to the periphery. The conic Columella gastropod columella is stout, with a strong lamellar fold at its insertion and two much more oblique ones anterior to it. ref name ... more details
is covered with a strong cuticle, shining. Nepionic shell is distinctly marked, with 4 whorl mollusc whorls , sculptured with strong narrow radial riblets, which on fourth whorl become obsolete ... spiral granulation which fades out upon last whorl, which is more coarsely sculptured by lengthwise ... insertion spreading upon the whorl and continued in a strong white callus across the parietal wall ... more details
elongate, acuminately spire mollusc spired , more or less livid in colour whorl mollusc whorls nine ... increases they are about nine in number on the penultimate whorl the last is encircled by about 13 and the keel which winds around its base is of a brown colour, and the portion of the whorl ... whorl 11 length of mouth 12 , width nearly 6. Operculum unguiculate, concentrically and transversely ... plications on the whorls, and the brown carina of the body whorl body whorl . It is difficult .... The callous band is quite conspicuous only about halfway around the body whorl, and then gradually ... more details
Italic title Taxobox name Maxwellia santarosana image regnum Animalia phylum Mollusca classis Gastropoda unranked superfamilia clade Caenogastropoda br clade Hypsogastropoda br clade Neogastropoda superfamilia Buccinoidea familia Muricidae subfamilia Muricopsidae genus Maxwellia species M. santarosana binomial Maxwellia santarosana binomial authority William Healey Dall Dall , 1905 synonyms ref ref name WoRMS Houart, R. 2009 . Maxwellia santarosana Dall, 1905 . Accessed through the World Register of Marine Species at http www.marinespecies.org aphia.php?p taxdetails&id 408590 on 26 December 2010 ref synonyms Murex fimbriatus A. Adams, 1854 not Brocchi Murex santarosana Dall, 1905 basionym Murexiella santarosana Dall, 1905 Maxwellia santarosana ref name WoRMS , common name the Santa Rosa, California Santa Rosa murex is a species of small predatory sea snail , a marine ocean marine gastropod mollusk in the family Muricidae , the rock snails. Description The size of the fusiform , varicose shell varies between 25 mm and 42 mm. The spire is higher than the other species in this genus and consists of six Whorl mollusc whorls . The hollow sutures are visible when not hidden by the subsequent whorl. The body whorl is rather broad and spindle shaped. The ovate Aperture mollusc aperture has a barely perceptible anal canal. The outer lip is finely crenulate but its inner surface is smooth. The columellar lip is smooth and callused. The siphonal canal is of moderate length and, as typical for this genus, fused on top, almost sealed below and pinting to the left at its base. the body whorl shows six prominent Varix mollusc varices , extending from the shoulder of the preceding whorl to the end of the siphonal canal. The shell Sculpture mollusc sculpture shows major and minor cords. The shell is white with the edge of each varix ochre brown. ref http books.google.be books?id Xj 2 KxUCcYC&pg PA529&dq 22Maxwellia 22&hl nl&ei 61wXTYHLJcqKhQegjbW3Dg&sa X&oi book result&ct result&res ... more details
Taxobox image Marginella huberti 001.jpg regnum Animalia phylum Mollusca classis Gastropoda unranked superfamilia clade Caenogastropoda br clade Hypsogastropoda br clade Neogastropoda superfamilia Muricoidea familia Marginellidae subfamilia Marginellinae genus Marginella species M. huberti binomial Marginella huberti binomial authority Clover, 1972 Marginella huberti is a species of colorful small sea snail , a marine ocean marine gastropod mollusc in the family biology family Marginellidae . Distribution This species occurs in Angola , south central Africa. Shell description The shell is 17 to 27 mm in length, 10 to 16 mm in greatest diameter, with a low conical spire and an indistinct suture. The outer lip is thickened, and strongly reflected outward, with a sharp edge overhanging the exterior of the body whorl mollusc whorl . The inside of the lip of the shell has 15 25 small irregular denticles, plus one very strong isolated denticle near its posterior end. The Aperture mollusc aperture is quite high for the genus, and it narrows both anteriorly and posteriorly. The first two apical whorls are pale brown. The remainder of the shell is beige with tiny ash grey dots arranged in spiral rows and looser wavy axial lines. There are small dark blotches serially arranged along the suture gastropod suture , and a larger series of crescentic blotches just above the shoulder of the body whorl. The areas between the shoulder and the suture, and along a band on the anterior part of the body whorl, are darker with blurred blotches some darker blotches or flames are also sometimes visible on the middle part of the body whorl. The outer lip has 15 to 25 dark grey streaks, often clustered in groups of 2 or 3, and mostly visible on the outermost, reflected part of the lip. Type material table border 0 width 60 cellspacing 0 cellpadding 0 tr td Holotype No.EE 3659 td td 18.8mm x 10.6mm td td Manchester Museum td tr tr td Paratype 1 td td align center ... td td P. Clover ... more details
Taxobox image Vertigo ronnebyensis shell.jpg image caption Shell of Vertigo ronnebyensis status NE status system status ref ref IUCN 2007. 2007 IUCN Red List of Threatened Species. www.iucnredlist.org . Downloaded on 19 September 2008. ref regnum Animal ia phylum Mollusc a classis Gastropod a superfamilia Pupilloidea familia Vertiginidae subfamilia Vertigininae tribus Vertiginini genus Vertigo genus Vertigo subgenus Vertigo species V. ronnebyensis binomial Vertigo ronnebyensis binomial authority Westerlund , 1871 ref Westerlund C. A. 1871. Expos critique des mollusques de terre et d eau douce de la Su de et de la Norv ge . pp. 1 2 , 1 200. Upsal. Berling . ref Vertigo ronnebyensis is a species of small land snail from the family Vertiginidae . Shell description gastropod shell Shell is deeply perforate, long ovate, regularly finely striate, very glossy and reddish brown in color. The shell has 5 convex whorl mollusc whorls . The body whorl last whorl is about equal to the penult, which is a third higher than the preceding whorl, which is double the height of the next earlier. Last whorl has a transverse callus of the same color near the aperture mollusc aperture . suture gastropod Suture is very oblique, ascending to the aperture. ref name Pilsbry Aperture is quite obliquely piriform, excised by the very oblique parietal wall. Aperture has 4 teeth 1 parietal lamella, 1 conic tooth at the lower end of the sharply emerging, dark colored columella mollusc columella 2 short, widely separated, deeply immersed palatal folds. Margins are delicately united, the outer margin is weakly arcuate, nearly straight, the columellar margin is broadly reflected. ref name Pilsbry The width of the adult shell is 1.15 1.35 mm, the height is 2.0 2.35 mm. ref http www.animalbase.uni goettingen.de zooweb servlet AnimalBase home species?id 1685 Species summary for Vertigo ronnebyensis . AnimalBase, accessed 23 June 2009. ref The width of the adult shell is 1.3 1.5 mm, the height is 2.3 2.5 ... more details
the whorl envelops a third of the previous. The whorl section is higher than wide with flattened flanks ... angular venter which may or may not have a keel. The whorl section is much higher than wide with the maximum ... more details
DISPLAYTITLE Naedyceras Group Taxobox name Naedyceras Group fossil range M Devonian image regnum Animalia phylum Mollusca classis Cephalopoda subclassis Nautiloidea ordo Oncocerida familia Brevicoceratidae subdivision ranks Genera subdivision Naedyceras , Gonionaedyceras , Gyronaedyceras authority The Naedyceras group is made up of three similar and closely related genera, Naedyceras , Gonionaedyceras , and Gyronaedyceras three gyroconic members of the Brevicoceratidae , within the nautiloid order Oncocerida . Naedyceras was named by Hyatt in 1884 Gonionaedyceras , and Gyronaedyceras by Flower in 1945. All three have open, gyroconic coiling, a subtriangular whorl section with a flattened dorsum. The siphuncle in each is ventral with flared out, cyrochoanitic septal necks and inwardly radial, blade like actinosiphonate developments. All three come from the Middle Devonian of North America N Am , specifically New York, Ohio, and Wisconsin. Differences lie primarily in the symmetry of the whorl section and in the suture. Genera Naedyceras Naedyceras is a brevicoceratid described as low spired, loosely coiled dextral torticones with flattned dorsum and subtriangular whorl section. The body chamber bulges slightly. The aperture in mature specimens is somewhat contracted. Sutures form slight lateral lobes, dorsal lobed, and broad ventral and umbilical saddles. Whorl section is symmetric Gonionaedyceras Gonionaedyceras strongly curved cyrtoconic brevicoceratids with an asymmetric subtriangular transverse section obliquely flattened inside, dorsal, curvature and narrowed outside, ventral, curvature with a rounded to angular ridge not in the plane of the siphuncle. Sutures have dorsal and lateral lobes and umbilical and ventral saddles. Umbilical saddles are sharper on the left than on the right. Ventral saddles are rounded. Gyronaedyceras Gyronaedyceras Compressed gyroconic brevicoceratids of about 2 volutions with an assymmnetrical, subtraingular whorl section having a bro ... more details
Taxobox fossil range fossilrange Callovian Oxfordian image regnum Animalia phylum Mollusca classis Cephalopoda subclassis Ammonoidea ordo Ammonitida superfamilia Perisphinctaceae familia Pachyceratidae familia authority Sydney S. Buckman Buckman , 1918 subdivision ranks Genera subdivision See Text Pachyceratidae is a family of Perisphinctaceae Perisphinctacean ammonite s from the upper Middle and lower Upper Jurassic. Genera within the Pachyceratidae have shells that are in general moderately involte but with most of the inner whorls exposed whorl sections subquadrate to subtrapezoidal, with rounded venter. Ribbing is strong, in some sharp. Primary ribs typically branch above mid flanks into twos, threes, and even fours. The Pachyceratidae, according to Donovan et al 1981 , were derived from the Perisphinctidae in the mid Callovian at about the same time as the longer lived Aspidoceratidae , lasting only into the subsequent Oxfordian stage Oxfordian . This differs from the perspective of Arkell, et al 1957 in the Treatise on Invertebrate Paleontology Treatise wherein the Pachyceridae is included in the Stephanocerataceae , derived from the Tulitidae and giving rise to the Mayaitidae. Genera, as described in the Treatise on Invertebrate Paleontology Treatise on Invertebrate Paleontology, Part L. 1957 Erymnoceras moderately involute primary ribs branch into mulitiple secondaries. M Callovian Callov . Erymnocerites , subgen of Erymoceras with more numerous secondary ribs. M Callov . Pachyerymnoceras involute, last whorl becoming compressed and Pachyceras like subgen of Erymnoceras . U Callov Rollierites evolute, more or less planulate ribs coarse, branching from tubercles at umbilical edge. M Callov . Pachyceras basically involute umbilical edge rounded, non tuberculate ribs fade on inner half of whorl sides last whorl commonly smooth or with ventral folds only. U Callov L Oxfordian stage Oxf . Tornquistes differs from Pachyceras s.s. by coarsening ribs on last whorl a ... more details
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