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Luehndea
From Williams et al., 2017:
[Luehndea, Morgenroth, 1970, p. 346–347: Emendations: Bucefalo Palliani et al., 1997b, p. 114–115; Riding and Helby, 2001a, p. 3, 5.
Type species: Luehndea spinosa, Morgenroth, 1970 (pl.9, fig.1)]
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Original description: [Morgenroth, 1970]:
Diagnosis:
Dinoflagellate cysts reflecting the following tabulation: 4`, 3a, 6``, 6c, 6```,1p, 1````. The archeopyle is formed by a rupture which starts on the dorsal side immediately above the cingulum on the epitract. Archeopyle type: AIP.
Affinities:
Luehndea can be distinguished from Ctenidodinium Deflandre 1938 in having three reflected anterior intercalary plates. Dapcodinium Evitt, 1961 from the Lias alpha differs from this in the reflected tabulation and probably in the type of the archeopyle, which appears to be apical in Dapcodinium.
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Modified descriptions:
Stover and Evitt 1978, p. 211-212:
Synopsis:
Cyst skolochorate, body ellipsoidal; paratabulation expressed by low parasutural ridges and gonal processes; combination epicystal archeopyle, Type tAtItP.
Description:
Shape: Body ellipsoidal; cyst outline, exclusive of spines, somewhat angular.
Wall relationships: Autophragm only.
Wall features: Parasutural ridges low and smooth; solid, tapered, distally acuminate gonal spines at most intersections of parasutural ridges. Autophragm smooth or ornamented with rows of granulae.
Paratabulation: Indicated by parasutural features, formula: 4`, 3a, 6``, 6c, 6```, 1p, 1````.
Archeopyle: Combination, Type tAtItP; operculum commonly separated, although may be attached.
Paracingulum: Indicated by low, transverse, parallel parasutural ridges. Parasulcus: Present mainly on the hypocyst; undivided, wider antapically than apically, and bordered by parasutural ridges.
Size: Small.
Affinities:
Luehndea differs from Ctenidodinium in having gonal spines and in having large dorsal intercalary paraplates. In Ctenidodinium, also, the crests of the parasutural ridges may be denticulate to spinose and, if the latter, the spines are not limited to gonal positions.
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Below, 1990, p. 37: (Translation: LPP)
Diagnosis:
Vesicle organisation/tabulation of dinoflagellate amphiesma PR, 4`, 3a, 6``, 7c, 6```, 2````, as, Xs, ps. Pentagonal 1```` and hexagonal 2```` partiform; large omegaform ps. Growth of thecal plates peridinioid.
Zygote cyst skolochorate to proximate, spheroidal, ovaloidal, ovoidal, polyhedric, cavate to acavate. Wall smooth or ornamented, paratabulation may be indicated: NR PR/XPR, NR`/4`, NRa/3a, NR``/6``, NRc/7c, NR```/6```, NR````/2````, NRs/as, Xs, ps; 2 antapicals partiform; archaeopyle epicystal, PR+1`+2`+3`+4`+1a+2a+3a+ 1``+2``+3``+4``+5``+6``. Operculum foederate, secate; general opercular formula (PR+1`+2`+3`+4`+1a+2a+3a+ 1``+2``+3``+4``+5``+6``)s.
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Emended description:
Bucefalo Palliani et al., 1997b:
Diagnosis:
Ellipsoidal to subspherical, frequently biconical, acavate dinoflagellate cysts, flattened dorso-ventrally. Small apical and antapical protuberances may be present. Cysts are proximochorate to chorate and small in size (of Stover and Evitt, 1978, p. 5). Autophragm smooth, micro-scabrate or microreticulate, occasionally ornamented with other low relief non-tabular elements. Paratabulation is generally evidenced by smooth, low to high parasutural ridges or crests. The parasutural ridges or crests may be variable in relief within individual specimens. Paratabulation formula: 4`, 3a, 6", 7c, 6"', 2"". Paraplate 1"" is five-sided while 2"" is six-sided (Plate I, 4). The hypocyst shows a partiform gonyaulacalean style. Gonal processes always occur and may be homomorphic or heteromorphic. They may be solid or hollow, conical or subconical or acicular and straight or sinuous. Distally the processes are generally acuminate. Archeopyle epicystal, type (E); operculum commonly adnate ventrally, although it may be free. Laevorotatory paracingulum indicated by low transverse parallel parasutural ridges; parasulcus mainly on the hypocyst, wider antapically than apically, and bordered by parasutural ridges.
Discussion:
The emendation of the original diagnosis of Morgenroth (1970), the modified description of Stover and Evitt (1978) and the modified diagnosis of Below (1990) is made principally to fully document the morphological variety of the gonal processes and of the autophragm, to indicate the presence of apical and antapical protuberances, and to fully document the variable morphology of the parasutures. We agree with the paratabulation formula of Luehndea given by Below (1990, p. 37), which includes two antapical paraplates. In Hungary, Luhndea has been recorded in the H. falciferum Zone (early Toarcian) (Baldanza et al., 1995), while in other localities its range top lies within the D. tenuicostatum Zone (early Toarcian) (Riding, 1984; Davies, 1985; De Vains, 1988; Prauss, 1989; Below, 1990; Feist-Burkhardt and Wille, 1992; Riding and Thomas, 1992; Bucefalo Palliani and Riding, 1997). Therefore the stratigraphical range of Luehndea is extended into the H.falciferum Zone. Fig. 3 summarises the morphological and stratigraphical differences between the three species of Luehndea.
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Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Luehndea Morgenroth, 1970, emend. Bucefalo Palliani et al., 1997b, was emended by Bucefalo Palliani et al. (1997b, p.115), who gave a paratabulation of 4`, 3a, 6", 7c, 6"' , 2"" and noted that the hypocyst is partiform. The archeopyle is epicystal, type (E), with the operculum commonly adnate ventrally, although it can be free.
[Luehndea, Morgenroth, 1970, p. 346–347: Emendations: Bucefalo Palliani et al., 1997b, p. 114–115; Riding and Helby, 2001a, p. 3, 5.
Type species: Luehndea spinosa, Morgenroth, 1970 (pl.9, fig.1)]
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Morgenroth, 1970]:
Diagnosis:
Dinoflagellate cysts reflecting the following tabulation: 4`, 3a, 6``, 6c, 6```,1p, 1````. The archeopyle is formed by a rupture which starts on the dorsal side immediately above the cingulum on the epitract. Archeopyle type: AIP.
Affinities:
Luehndea can be distinguished from Ctenidodinium Deflandre 1938 in having three reflected anterior intercalary plates. Dapcodinium Evitt, 1961 from the Lias alpha differs from this in the reflected tabulation and probably in the type of the archeopyle, which appears to be apical in Dapcodinium.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Modified descriptions:
Stover and Evitt 1978, p. 211-212:
Synopsis:
Cyst skolochorate, body ellipsoidal; paratabulation expressed by low parasutural ridges and gonal processes; combination epicystal archeopyle, Type tAtItP.
Description:
Shape: Body ellipsoidal; cyst outline, exclusive of spines, somewhat angular.
Wall relationships: Autophragm only.
Wall features: Parasutural ridges low and smooth; solid, tapered, distally acuminate gonal spines at most intersections of parasutural ridges. Autophragm smooth or ornamented with rows of granulae.
Paratabulation: Indicated by parasutural features, formula: 4`, 3a, 6``, 6c, 6```, 1p, 1````.
Archeopyle: Combination, Type tAtItP; operculum commonly separated, although may be attached.
Paracingulum: Indicated by low, transverse, parallel parasutural ridges. Parasulcus: Present mainly on the hypocyst; undivided, wider antapically than apically, and bordered by parasutural ridges.
Size: Small.
Affinities:
Luehndea differs from Ctenidodinium in having gonal spines and in having large dorsal intercalary paraplates. In Ctenidodinium, also, the crests of the parasutural ridges may be denticulate to spinose and, if the latter, the spines are not limited to gonal positions.
------------------------------------------
Below, 1990, p. 37: (Translation: LPP)
Diagnosis:
Vesicle organisation/tabulation of dinoflagellate amphiesma PR, 4`, 3a, 6``, 7c, 6```, 2````, as, Xs, ps. Pentagonal 1```` and hexagonal 2```` partiform; large omegaform ps. Growth of thecal plates peridinioid.
Zygote cyst skolochorate to proximate, spheroidal, ovaloidal, ovoidal, polyhedric, cavate to acavate. Wall smooth or ornamented, paratabulation may be indicated: NR PR/XPR, NR`/4`, NRa/3a, NR``/6``, NRc/7c, NR```/6```, NR````/2````, NRs/as, Xs, ps; 2 antapicals partiform; archaeopyle epicystal, PR+1`+2`+3`+4`+1a+2a+3a+ 1``+2``+3``+4``+5``+6``. Operculum foederate, secate; general opercular formula (PR+1`+2`+3`+4`+1a+2a+3a+ 1``+2``+3``+4``+5``+6``)s.
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Emended description:
Bucefalo Palliani et al., 1997b:
Diagnosis:
Ellipsoidal to subspherical, frequently biconical, acavate dinoflagellate cysts, flattened dorso-ventrally. Small apical and antapical protuberances may be present. Cysts are proximochorate to chorate and small in size (of Stover and Evitt, 1978, p. 5). Autophragm smooth, micro-scabrate or microreticulate, occasionally ornamented with other low relief non-tabular elements. Paratabulation is generally evidenced by smooth, low to high parasutural ridges or crests. The parasutural ridges or crests may be variable in relief within individual specimens. Paratabulation formula: 4`, 3a, 6", 7c, 6"', 2"". Paraplate 1"" is five-sided while 2"" is six-sided (Plate I, 4). The hypocyst shows a partiform gonyaulacalean style. Gonal processes always occur and may be homomorphic or heteromorphic. They may be solid or hollow, conical or subconical or acicular and straight or sinuous. Distally the processes are generally acuminate. Archeopyle epicystal, type (E); operculum commonly adnate ventrally, although it may be free. Laevorotatory paracingulum indicated by low transverse parallel parasutural ridges; parasulcus mainly on the hypocyst, wider antapically than apically, and bordered by parasutural ridges.
Discussion:
The emendation of the original diagnosis of Morgenroth (1970), the modified description of Stover and Evitt (1978) and the modified diagnosis of Below (1990) is made principally to fully document the morphological variety of the gonal processes and of the autophragm, to indicate the presence of apical and antapical protuberances, and to fully document the variable morphology of the parasutures. We agree with the paratabulation formula of Luehndea given by Below (1990, p. 37), which includes two antapical paraplates. In Hungary, Luhndea has been recorded in the H. falciferum Zone (early Toarcian) (Baldanza et al., 1995), while in other localities its range top lies within the D. tenuicostatum Zone (early Toarcian) (Riding, 1984; Davies, 1985; De Vains, 1988; Prauss, 1989; Below, 1990; Feist-Burkhardt and Wille, 1992; Riding and Thomas, 1992; Bucefalo Palliani and Riding, 1997). Therefore the stratigraphical range of Luehndea is extended into the H.falciferum Zone. Fig. 3 summarises the morphological and stratigraphical differences between the three species of Luehndea.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Luehndea Morgenroth, 1970, emend. Bucefalo Palliani et al., 1997b, was emended by Bucefalo Palliani et al. (1997b, p.115), who gave a paratabulation of 4`, 3a, 6", 7c, 6"' , 2"" and noted that the hypocyst is partiform. The archeopyle is epicystal, type (E), with the operculum commonly adnate ventrally, although it can be free.