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Lingulodinium multivirgatum
multivirgatum de Verteuil and Norris, 1996a, p.118,120,122, pl.4, figs.1-14; pl.18, fig.7.
Holoptype: de Verteuil and Norris, 1996a, pl.4, figs.4-6.
Locus typicus: Popes Creek Section, Potomac River, Popes Creek, Charles County, Maryland.
Stratum typicum: The lower Miocene Fairhaven Member of the Calvert Formation.
Age: Early Miocene.
Original diagnosis: de Verteuil and Norris, 1996, 118: Lingulodinium multivirgatum
A species of Lingulodinium characterized by cysts having many nontabular, closely spaced virgae that are simple, hollow, distally closed and acuminate to evexate; archeopyle Type 3P.
Original description: de Verteuil and Norris, 1996, 118, 120: Lingulodinium multivirgatum
Cyst intermediate, proximate or rarely marginally proximochorate, spherical or less commonly subspherical. The wall structure is uniform about the cyst and comprises homogeneous pedium, ca.0.5Ám thick, and closely spaced pila (singular pilum; sensu Erdtman 1952) of even or uneven height. These structural elements range from 0.5 to 2.0Ám in length and are ca. 0.25Ám in diameter, and give a granulate to dense setose texture to the wall surface. The virgae are nontabular, closely and evenly spaced 2 to 10Ám apart, and are 2 to 9Ám in length or from 3 % to 12 % of cyst diameter. Virgae are formed by homogeneous, scabrate to irregularly microgranulate tegillum, attach directly to the pedium, and are hollow, distally closed, and tapered acuminate to evexate. The archeopyle is polyplacoid, Type 3P; formed from the geniculate inferred third precingular field and both adjacent precingulars. Cingulum sulcus, and tabulation not indicated, except by the archeopyle.
Dimensions: Maximum diameter excluding virgae 47(58.6)72Ám, holotype 55Ám. Virgae 2-9Ám. Twenty-seven specimens measured.
Discussion: de Verteuil and Norris, 1996, 118, 120
Lingulodinium multivirgatum occurs only infrequently in a restricted interval in the lower Miocene in the middle U.S. Atlantic Coastal Plain (Part I, this volume). In most specimens the virgae are 4 to 6Ám long, tapered, and distally acuminate with a circular base 1 to 2Ám in diameter. Other specimens have distally rounded, evexate virgae of similar or slightly greater length, also with circular bases ] to 2Ám in diameter. In most samples in which it was recorded, Lingulodinium multivirgatum co-occurs with the familar Lingulodinium machaerophorum. In some cases it is difficult to assign specimens to one or the other species but usually the combination of appendage length, morphology and spacing make the distinction clear. Specimens of intermediate morphology usually occur at the upper end of the stratigraphic range of Lingulodinium multivirgatum (e.g. pl. 4, figs. 11 - 13). They differ from Pleistocene and Holocene specimens of Lingulodinium machaerophorum with short processes in that the appendages, although distally rounded, are still tapered and lack the distal granules commonly observed on Lingulodinium machaerophorum.
In all of the more complete specimens observed, the archeopyle included fields from the precingular series only; we did not see any specimens with an unequivocal combination archeopyle involving climactal fields.
Comparison: de Verteuil and Norris, 1996, 118, 120
Lingulodinium multivirgatum differs from the type species of this genus, Lingulodinium machaerophorum, in having more densely spaced appendages that are usually less than 10% of cyst diameter and are typically acuminate. Rarely, specimens of Lingulodinium machaerophorum do occur with short appendages in this range but even then they are evexate to distally bulbous and less numerous and closely spaced. Specimens of this morphology have been assigned by Matsuoka and Bujak to the taxon Lingulodinium brevispinosum Matsuoka and Bujak 1988 (see redescription in Head 1994a), which we consider a junior synonym of Lingulodinium machaerophorum, based on de Verteuil"s examination of the holotype and paratype specimens. Lingulodinium multivirgatum is otherwise most similar to Lingulodinium xanthium which has low, closely spaced, acuminate processes and a Type 2P archeopyle. The photomicrograph of Lingulodinium xanthium in Benedek and Sarjeant (1981) suggests that the two taxa are indeed similar. However, they describe the wall structure of Lingulodinium xanthium as having "a fine meshwork of low ridges" and appendages that are "conspicuously fibrous, towards their proximal ends, the fibres confluent with surficial ridges" (p. 342). In Lingulodinium multivirgatum the proximate luxuriae do not form any structures resembling ridges or crests or a reticulum or fibropitted network; the tegillum of which the virgae are formed is not fibrous but rather is scabrate.
Occurrence: Lower Miocene (DN2 - DN3) in the Salisbury Embayment. Specimens belonging to Zone DN2 are present at 475 " in the ACGS-4 Core from New Jersey (Part I, this volume). Lingulodinium multivirgatum is most common in the Popes Creek Sand Member and the lower part of the Fairhaven Member of the Calvert Formation, becoming rare in the upper part of the Fairhaven Member and in the lowermost beds of the Plum Point Marls Member. Lingulodinium multivirgatum is present in upper Oligocene strata trom ODP Site 903 off New Jersey, which predate Zone DNl (de Verteuil, unpub.).
Remarks: Biffi and Manum (1988) recorded a taxon as Lingulodinium sp. 1 from the earliest Miocene (NNl - NN2?) of the Marche region of central Italy. Their specimens have evexate virgae and appear to belong to Lingulodinium multivirgatum.
Holoptype: de Verteuil and Norris, 1996a, pl.4, figs.4-6.
Locus typicus: Popes Creek Section, Potomac River, Popes Creek, Charles County, Maryland.
Stratum typicum: The lower Miocene Fairhaven Member of the Calvert Formation.
Age: Early Miocene.
Original diagnosis: de Verteuil and Norris, 1996, 118: Lingulodinium multivirgatum
A species of Lingulodinium characterized by cysts having many nontabular, closely spaced virgae that are simple, hollow, distally closed and acuminate to evexate; archeopyle Type 3P.
Original description: de Verteuil and Norris, 1996, 118, 120: Lingulodinium multivirgatum
Cyst intermediate, proximate or rarely marginally proximochorate, spherical or less commonly subspherical. The wall structure is uniform about the cyst and comprises homogeneous pedium, ca.0.5Ám thick, and closely spaced pila (singular pilum; sensu Erdtman 1952) of even or uneven height. These structural elements range from 0.5 to 2.0Ám in length and are ca. 0.25Ám in diameter, and give a granulate to dense setose texture to the wall surface. The virgae are nontabular, closely and evenly spaced 2 to 10Ám apart, and are 2 to 9Ám in length or from 3 % to 12 % of cyst diameter. Virgae are formed by homogeneous, scabrate to irregularly microgranulate tegillum, attach directly to the pedium, and are hollow, distally closed, and tapered acuminate to evexate. The archeopyle is polyplacoid, Type 3P; formed from the geniculate inferred third precingular field and both adjacent precingulars. Cingulum sulcus, and tabulation not indicated, except by the archeopyle.
Dimensions: Maximum diameter excluding virgae 47(58.6)72Ám, holotype 55Ám. Virgae 2-9Ám. Twenty-seven specimens measured.
Discussion: de Verteuil and Norris, 1996, 118, 120
Lingulodinium multivirgatum occurs only infrequently in a restricted interval in the lower Miocene in the middle U.S. Atlantic Coastal Plain (Part I, this volume). In most specimens the virgae are 4 to 6Ám long, tapered, and distally acuminate with a circular base 1 to 2Ám in diameter. Other specimens have distally rounded, evexate virgae of similar or slightly greater length, also with circular bases ] to 2Ám in diameter. In most samples in which it was recorded, Lingulodinium multivirgatum co-occurs with the familar Lingulodinium machaerophorum. In some cases it is difficult to assign specimens to one or the other species but usually the combination of appendage length, morphology and spacing make the distinction clear. Specimens of intermediate morphology usually occur at the upper end of the stratigraphic range of Lingulodinium multivirgatum (e.g. pl. 4, figs. 11 - 13). They differ from Pleistocene and Holocene specimens of Lingulodinium machaerophorum with short processes in that the appendages, although distally rounded, are still tapered and lack the distal granules commonly observed on Lingulodinium machaerophorum.
In all of the more complete specimens observed, the archeopyle included fields from the precingular series only; we did not see any specimens with an unequivocal combination archeopyle involving climactal fields.
Comparison: de Verteuil and Norris, 1996, 118, 120
Lingulodinium multivirgatum differs from the type species of this genus, Lingulodinium machaerophorum, in having more densely spaced appendages that are usually less than 10% of cyst diameter and are typically acuminate. Rarely, specimens of Lingulodinium machaerophorum do occur with short appendages in this range but even then they are evexate to distally bulbous and less numerous and closely spaced. Specimens of this morphology have been assigned by Matsuoka and Bujak to the taxon Lingulodinium brevispinosum Matsuoka and Bujak 1988 (see redescription in Head 1994a), which we consider a junior synonym of Lingulodinium machaerophorum, based on de Verteuil"s examination of the holotype and paratype specimens. Lingulodinium multivirgatum is otherwise most similar to Lingulodinium xanthium which has low, closely spaced, acuminate processes and a Type 2P archeopyle. The photomicrograph of Lingulodinium xanthium in Benedek and Sarjeant (1981) suggests that the two taxa are indeed similar. However, they describe the wall structure of Lingulodinium xanthium as having "a fine meshwork of low ridges" and appendages that are "conspicuously fibrous, towards their proximal ends, the fibres confluent with surficial ridges" (p. 342). In Lingulodinium multivirgatum the proximate luxuriae do not form any structures resembling ridges or crests or a reticulum or fibropitted network; the tegillum of which the virgae are formed is not fibrous but rather is scabrate.
Occurrence: Lower Miocene (DN2 - DN3) in the Salisbury Embayment. Specimens belonging to Zone DN2 are present at 475 " in the ACGS-4 Core from New Jersey (Part I, this volume). Lingulodinium multivirgatum is most common in the Popes Creek Sand Member and the lower part of the Fairhaven Member of the Calvert Formation, becoming rare in the upper part of the Fairhaven Member and in the lowermost beds of the Plum Point Marls Member. Lingulodinium multivirgatum is present in upper Oligocene strata trom ODP Site 903 off New Jersey, which predate Zone DNl (de Verteuil, unpub.).
Remarks: Biffi and Manum (1988) recorded a taxon as Lingulodinium sp. 1 from the earliest Miocene (NNl - NN2?) of the Marche region of central Italy. Their specimens have evexate virgae and appear to belong to Lingulodinium multivirgatum.