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Carpatella cornuta
Carpatella cornuta, Grigorovich, 1969a; Emendations: Fechner and Mohr, 1986, Damassa, 1988
Holotype: Grigorovich, 1969, pl.1, fig.1 (lost according to Damassa, 1988)
Neotype: Damassa, 1988, pl.1, figs.1,4,7 (designated by Damassa, 1988)
Locus typicus: District of Lwow, Karpathians, Russia
Stratum typicum: Danian
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Original diagnosis: [Grigorovich, 1969, p.74]: (Translation: LPP):
Diagnosis:
Shell circular with on apical and one antapical horn. Transitudional furrow clear and ring-like, dividing the shell into two equal parts. Eptheca hemisphaerical with short apical horn.
Tabulation clearly indicated. Tabulation formula: ?3', 6'', 3p. Hypotheca nearly symmetrically to epitheca with a small protrusion of more or less the same size as the apical horn. Tabulation formula 5-6''', 1''''. Sutures broad and thickened, without ornamentation.
Archaeopyle large, precingular (3''). Often operculum in situ.
Surface granulate.
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Supplemental description:
Hultberg, 1985, p.112:
Description:
Cornucavate cyst, composed of endophragm and periphragm, closely appressed, except at the apical and antapical protrusions.
The surface of the endophragm is smooth. The surface of the periphragm is granulate. The cyst-wall is very thick (up to 7 µm) and dark in color. The shape of the cyst is rounded ellipsoidal, with a rounded protrusion at each pole.
Paratabulation is expressed by faint, granulate lineations in the periphragm.
The paratabulation is gonyaulacacean, paratabulation formula: 4', 6", xc, 6''', 1''''.
The boundary between paraplates 2' and 3' is mostly obscured by the large archeopyle. The archeopyle is precingular, type P, formed by the detachment of paraplate 3". Operculum free. The archeopyle appears to be enlarged.
Paracingulum is indicated by low ridges in the periphragm. The individual paraplates of the parasulcus are often discernible.
Dimensions:
106-113 µm (length), 85-93 µm (breadth).
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Emended description:
Damassa, 1988, p. 170-172:
Synopsis:
Proximate cysts, subspherical to ellipsoidal in shape, having a short horn at apex and antapex.
Sexiform gonyaulacacean paratabulation indicated by parasutural features. Ventral organization L-type. Apical paraplate A (4') contacts B (2') dorsal to preapical P; paraplate Q is absent; precingular li (6") contacts both A and lu (1 '); Iu (1 "') and II (2"') relatively small, ai (as) contacts II (2"'), Iu (1"') does not contact au (lc); X (lp) and Z (ps) elongate, arcuate; antapical Y (1"") slightly asymmetrical-oblong; postcingular parasuture IV/V (4"'/5"') offset to the left of precingular parasuture 4/5 (3"/4").
Archeopyle precingular, Type P, precingular 4 (3") only, with rounded pentagonal margin; operculum free.
Wall consists of autophragm only, outer part densely fibrous or spongy in appearance, inner surface of wall smooth. Porichnion visible between apical paraplates A and lu with SEM.
Description:
Shape: Cysts subspherical to ellipsoidal in ventro-dorsal or lateral view, with single short horns at apex and antapex; approximately circular in polar view; slight indentation in sulcal region. Horns are solid structures formed from densely fibrous, spongy wall material, not by protrusion of the entire wall, nor by coalescing parasutural features (Plate 1, figs. 5, 9).
Size: Intermediate to large. Length of cysts approximately 100- 130 µm, including horns (length of horns approximately 10-18 µm); equatorial diameter approximately 90-100 µm.
Wall structure: Cysts proximate and acavate, wall consisting of autophragm only. Surface texture densely fibrous; in cross section wall appears spongy, having a smooth inner surface (Plate 3, fig. 3; see arrow). There is a discontinuity within the wall, but no obvious change in texture. Wall thickness approximately 5-8 µm.
Archeopyle: Precingular archeopyle, Type P, consisting of paraplate 4 (3") only; rounded pentagonal in shape and may be slightly enlarged. Operculum free. Wall is distinctly thinner at margins of archeopyle and operculum (Plate 1, figs. 2, 3).
Surface features: Paratabulation indicated by narrow parasutural "furrows" flanked by somewhat broader raised bands (Plate 1, fig. 6; Plate 3, fig. 4). Intratabular ornament consists of parallel rows of small "pits" visible with SEM on some specimens, generally restricted to larger paraplates (e.g., Plate 3, figs. 1, 2; compare with intratabular ridges of Cribroperidinium).
Paratabulation: A complete sexiform gonyaulacoid paratabulation, essentially equivalent to the Ventriosum pattern, Aptiana-Ventriosum complex, of Helenes (1986), is indicated by parasutural features (Text-Figure 3): 1 preapical (P = pr); 4 apicals (lu, A, B, C = 1'-4'); 6 precingulars (2, 3, 4, 5, 6, and li = 1"-6"); 6 cingulars (au, b, c, d, e, and fi = lc-6c); 6 sulcals (ai, fu, Ii, Im, Iu and Z = as, ras, rs, ls, 1 "' and ps); 5 postcingulars (II, III, IV, V, and VI = 2"'-6"'); 1 posterior intercalary (X = lp); and 1 antapical (Y = 1""). In Kofoidian terms the paratabulation formula is: lpr, 4', 6", 6c, 6s, 5"' 1 p, 1"". The paratabulation pattern is characterized by an L-type ventral configuration. Apical paraplates A and B (4' and 2') are in contact dorsal to P; Q is not present. Paraplates lu and li ( 1 ' and 6") are in contact in the ventral region (li is camerate and also contacts A; ai is planate). Paraplates lu and A are elongate, and a porichnion can be observed with the SEM on the edge of lu adjacent to the lu/A parasuture (Plate 2, fig. 3). In the sulcal region, most specimens of Carpatella exhibit a configuration in which paraplate ai (as) contacts II (2"'), but Iu ( 1 "') does not contact au (lc); thus Iu is not a postcingular paraplate (in the strict Kofoidian sense) because it does not contact the paracingulum. The length of the ai/II (as/2"') contact is variable (see Plate 1, figs. 1, 4; Plate 2, figs. 2, 6; Text-Figure 3A), and several specimens were observed with a four-way contact between paraplates ai, II, Iu and au. In contrast, most species having a Ventriosum pattern are characterized by a contact between paraplates Iu and au. In Carpatella, as in other species having the Ventriosum pattern, Iu and II are relatively small, the remaining postcingular paraplates (III-VI or 3"'- 6"') are distinctly larger. Postcingular parasuture IV/V is offset to the left of precingular parasuture 4/5, but does not attain a truly mid-dorsal position. Antapical paraplate Y (1"") is slightly asymmetrical-oblong, contacting paraplates X (lp), Z (ps) and III-VI (3"'-6"'). Antapical parasutures Y/X, Y/Z and Y/VI are relatively short, and may be nearly co-linear. Parasuture Y/V is only slightly longer than Y/III (see Helenes, 1986, p. 78-79).
Remarks:
Carpatella is not alone in having six sulcal and only five postcingular paraplates (speaking in the strict Kofoidian sense). The ai/II contact which eliminates Iu from the ranks of the postcingular paraplates, also occurs in all species assigned to Ctenidodinium, Leptodinium, Occisucysta, Tehamadinium and Korystocysta, in Gonyaulacysta dualis (Helenes, 1986), and in several species of Hystrichokolpoma (Damassa et al., 1987). Neotype. The specimen designated as the neotype of Carpatella cornuta is that illustrated in Plate 1, figs. 1, 4, 7: Amoco Production Company Locality No. 6720, C. Limhamn, southwestern Sweden, sample P 44601, slide A01, R 15.4, + 9.9. Designation of a neotype is appropriate in cases where the holotype and all other type material is missing (ICBN, 1983, Art. 7.8; see discussion). The neotype is stored at Amoco Production Company Research Center, Tulsa, Oklahoma. Comparison. At present Carpatella is a monotypic genus. It has been distinguished from Apteodinium, which is similar in overall appearance (e.g. shape, wall texture, size), on the basis of the presence of both apical and antapical horns (Stover and Evitt, 1978, p. 144). In addition, species of Apteodinium tend to lack clear evidence of paratabulation (Stover and Evitt, 1978); however, see Lucas-Clark (1987) for a partial Aptiana-Ventriosum paratabulation scheme. It is apparent that Carpatella cornuta possesses features of paratabulation, archeopyle and wall structure nearly identical to species of Cribroperidinium (Helenes, 1984). The two genera may be distinguished on the basis of the development of a second (antapical) horn in Carpatella and in the morphologic details by which the paratabulation is expressed (parasutural furrows and intratabular "pits" in Carpatella, parasutural ridges and intratabular ridges in Cribroperidinium). The only difference in paratabulation observed between these genera is in the configuration of the ai/ II-Iu/au contacts (Iu/au in Cribroperidinium, ai/II in most specimens of C. cornuta).
Discussion: (p. 174,175):
Since Grigorovich's original description of Carpatella cornuta in 1969, there have been relatively few occurrences reported in the literature. Specimens illustrated by Morgenroth (1968, p. 542- 544, pl. 44, figs. 1-3) and Evitt (1973, p. 34, pl. 1, figs. 12-14) were identified as "Danea mutabilis." Other occurrences reported as Carpatella cornuta include those by Hansen (1977, pl. 7, fig. 2 lF; 1979, p. 137, fig 5), Hultberg (1985, p. 61, pl. 1, figs. 3, 4, p. 112, pl.2,fig.C; 1986,p.38,pl. 1,figs.3,4),and Firth (1987, pl. 3, fig. 6). I am certain that Hansen's, Hultberg's and Firth's specimens are conspecific with my material, and am reasonably confident of the identification of Morgenroth's and Evitt's specimens as C. cornuta; however, I have serious doubts regarding the identity of those specimens described as C. cornuta by Fechner and Mohr (1986, p. 181-188, figs. 2, 3). Although their description corresponds fairly well in general terms to my concept of Carpatella, there are several differences in details of morphology and paratabulation between their specimens and those described here (see Fechner and Mohr, 1986, fig. 3). The apical horn is described as having formed from four apical parasutural crests, in contrast to the simple structure illustrated here. Also, the denticulate crests ("Kamme") noted by Fechner and Mohr (1986, p. 184) have not been reported in other specimens assigned to Carpatella, and are certainly not evident in the material used in this study. The paratabulation differs in the Moroccan material as follows: apical lu (1') is longer, and ai (as) is shorter than in specimens from Scandinavia; X (1 p) and Z (ps) do not show the arcuate shape typical of Cribroperidinium and its allies; there is no contact shown between ai (as) and II (2"'); no contact is shown between A (4') and B (2') dorsal to P (pr). Finally, the stratigraphic position of their specimens is anomalous, as C. cornuta previously has been reported only from Danian deposits. There is some question as to whether the material used in the present study is conspecific with the specimens described by Grigorovich in 1969, because neither I nor other authors (to my knowledge) have seen the holotype or other type material of C. cornuta. Indeed, it may be that no one knows what Carpatella cornuta really is! Comparison of the Scandinavian material with Grigorovich's illustrations (1969, figs. 1-6) demonstrates a general morphologic correspondence between the two, but details of paratabulation and other features cannot be determined with confidence. J. K. Lentin (oral commun., 1986) stated that she tried to locate the type specimen or other type material while she was in the Soviet Union, but was unsuccessful. If a holotype is missing, and additional type material is unavailable, it is appropriate to designate a neotype, which then serves as the type "as long as all of the material on which the name of the taxon is based is missing" (ICBN, 1983, Art. 7.8). Should the holotype or other type material be recovered, the neotype would no longer be needed. (Or, if the material described here is not identical to the original type material, a new name would be required for the Scandinavian material.) Many specimens of Carpatella correspond exactly to the synopsis and description of Cribroperidinium published by Helenes (1984) - even in possession of intratabular structures (Plate 3, fig. 1). The nearly complete morphologic overlap between the two genera presents a strong case for consideration of Carpatella as a junior synonym of Cribroperidinium. Both Helenes (1984) and Damassa (1984) argued that paratabulation should be considered before other aspects of cyst morphology in generic and suprageneric classification. The minor difference in paraplate configuration between Cribroperidinium and Carpatella (involving contacts of paraplates ai, II, Iu and au = as? 2"', 1"' and lc) does not imply a fundamental difference in paraplate topology; but instead (considering the high degree of mobility characteristic of paraplates in the sulcal region), may be seen as an interspecific or intergeneric variable. Note that in the specimen designated as the neotype (Plate 1, figs. 1, 4, 7), the ai/II contact is extremely short, while in other specimens (e.g. Plate 2, fig. 2) it is noticeably longer. In other aspects of morphology, Carpatella can be distinguished from Cribroperidinium only by the presence of an antapical horn and in the morphologic expression of features of paratabulation--features which for many other genera would be considered at the specific level. Despite the obvious similarities between C. cornuta and species of Cribroperidinium, it seems preferable to designate a neotype and retain C. cornuta as a separate (though isolated) species until the questions regarding the holotype are resolved. Regardless of the eventual taxonomic placement of Carpatella cornuta, the species remains an easily recognized and, geologically speaking, short-lived form a "Shakespearean rose" and a biostratigrapher's delight.
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Stratigraphic and Geographic Range:
The samples included in this study range in age from zone NP 1 to NP 3 (Danian). C. cornuta originally was described from Danian deposits in the Carpathian Mountains (Grigorovich, 1969). Additional occurences of C. cornuta have been reported from sediments of Danian age in Scandinavia (Morgenroth, 1968 [as Danea mutabilis]; Hansen, 1977, 1979; Kjellstrom and Hansen, 1981; Damassa, 1985; Hultberg, 1985, 1986), North America (Evitt, 1973 [as Danea mutabilis]; Firth, 1987) and Tunisia (Damassa, unpubl. observations). The Eocene occurrence in South Morocco reported by Fechner and Mohr (1986), if valid, is the first known occurrence of this species above the Danian (see discussion). C. cornuta has also been recorded from presumably uppermost Maastrichtian sediments, i.e., it occurs with Palynodinium grallator Gocht 1970 (an uppermost Maastrichtian form; Hansen, 1977) in the top Maastrichtian sample at W. Limhamn and in the Stevns Klint at Hojerup (Damassa, unpubl. observations). (Unfortunately, the Maastrichtian specimens of Carpatella are not well preserved-there remains some doubt as to their identity.) Hansen (1977) and Hultberg (1985, 1986), who also studied Scandinavian material, did not report a co-occurrence of these species. Firth (1987) depends on the separate occurrences of C. cornuta and P. grallator to determine the location of the Maastrichtian-Danian boundary in the southeastern United States. It may be that these species occur together only in stratigraphically complete sections, or that reworking of P. grallator has occurred in the sections used in this study.
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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.
Carpatella cornuta Grigorovich, 1969a, emend. Fechner and Mohr, 1986, emend. Damassa, 1988. According to Damassa (1988), this is a proximate cyst, subspherical to ellipsoidal with a short horn at the apex and antapex. Sexiform gonyaulacacean tabulation indicated by parasutural features. Ventral organization L type. No Q plate. 1"’ and 2"’ are relatively small. 1"’ does not contact the 1c plate. 1p and ps are elongate arcuate, 1"” is slightly asymmetrical oblong; 4"’/5"’ suture offset. Wall consists of autophragm only, outer part densely fibrous or spongy, inner surface smooth. Porichnion visible between apical paraplates. Archeopyle is precingular resulting from the loss of the 3" paraplate.
Size: length including horns 100-130 µm, width 90-100 µm.
Holotype: Grigorovich, 1969, pl.1, fig.1 (lost according to Damassa, 1988)
Neotype: Damassa, 1988, pl.1, figs.1,4,7 (designated by Damassa, 1988)
Locus typicus: District of Lwow, Karpathians, Russia
Stratum typicum: Danian
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Original diagnosis: [Grigorovich, 1969, p.74]: (Translation: LPP):
Diagnosis:
Shell circular with on apical and one antapical horn. Transitudional furrow clear and ring-like, dividing the shell into two equal parts. Eptheca hemisphaerical with short apical horn.
Tabulation clearly indicated. Tabulation formula: ?3', 6'', 3p. Hypotheca nearly symmetrically to epitheca with a small protrusion of more or less the same size as the apical horn. Tabulation formula 5-6''', 1''''. Sutures broad and thickened, without ornamentation.
Archaeopyle large, precingular (3''). Often operculum in situ.
Surface granulate.
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Supplemental description:
Hultberg, 1985, p.112:
Description:
Cornucavate cyst, composed of endophragm and periphragm, closely appressed, except at the apical and antapical protrusions.
The surface of the endophragm is smooth. The surface of the periphragm is granulate. The cyst-wall is very thick (up to 7 µm) and dark in color. The shape of the cyst is rounded ellipsoidal, with a rounded protrusion at each pole.
Paratabulation is expressed by faint, granulate lineations in the periphragm.
The paratabulation is gonyaulacacean, paratabulation formula: 4', 6", xc, 6''', 1''''.
The boundary between paraplates 2' and 3' is mostly obscured by the large archeopyle. The archeopyle is precingular, type P, formed by the detachment of paraplate 3". Operculum free. The archeopyle appears to be enlarged.
Paracingulum is indicated by low ridges in the periphragm. The individual paraplates of the parasulcus are often discernible.
Dimensions:
106-113 µm (length), 85-93 µm (breadth).
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Emended description:
Damassa, 1988, p. 170-172:
Synopsis:
Proximate cysts, subspherical to ellipsoidal in shape, having a short horn at apex and antapex.
Sexiform gonyaulacacean paratabulation indicated by parasutural features. Ventral organization L-type. Apical paraplate A (4') contacts B (2') dorsal to preapical P; paraplate Q is absent; precingular li (6") contacts both A and lu (1 '); Iu (1 "') and II (2"') relatively small, ai (as) contacts II (2"'), Iu (1"') does not contact au (lc); X (lp) and Z (ps) elongate, arcuate; antapical Y (1"") slightly asymmetrical-oblong; postcingular parasuture IV/V (4"'/5"') offset to the left of precingular parasuture 4/5 (3"/4").
Archeopyle precingular, Type P, precingular 4 (3") only, with rounded pentagonal margin; operculum free.
Wall consists of autophragm only, outer part densely fibrous or spongy in appearance, inner surface of wall smooth. Porichnion visible between apical paraplates A and lu with SEM.
Description:
Shape: Cysts subspherical to ellipsoidal in ventro-dorsal or lateral view, with single short horns at apex and antapex; approximately circular in polar view; slight indentation in sulcal region. Horns are solid structures formed from densely fibrous, spongy wall material, not by protrusion of the entire wall, nor by coalescing parasutural features (Plate 1, figs. 5, 9).
Size: Intermediate to large. Length of cysts approximately 100- 130 µm, including horns (length of horns approximately 10-18 µm); equatorial diameter approximately 90-100 µm.
Wall structure: Cysts proximate and acavate, wall consisting of autophragm only. Surface texture densely fibrous; in cross section wall appears spongy, having a smooth inner surface (Plate 3, fig. 3; see arrow). There is a discontinuity within the wall, but no obvious change in texture. Wall thickness approximately 5-8 µm.
Archeopyle: Precingular archeopyle, Type P, consisting of paraplate 4 (3") only; rounded pentagonal in shape and may be slightly enlarged. Operculum free. Wall is distinctly thinner at margins of archeopyle and operculum (Plate 1, figs. 2, 3).
Surface features: Paratabulation indicated by narrow parasutural "furrows" flanked by somewhat broader raised bands (Plate 1, fig. 6; Plate 3, fig. 4). Intratabular ornament consists of parallel rows of small "pits" visible with SEM on some specimens, generally restricted to larger paraplates (e.g., Plate 3, figs. 1, 2; compare with intratabular ridges of Cribroperidinium).
Paratabulation: A complete sexiform gonyaulacoid paratabulation, essentially equivalent to the Ventriosum pattern, Aptiana-Ventriosum complex, of Helenes (1986), is indicated by parasutural features (Text-Figure 3): 1 preapical (P = pr); 4 apicals (lu, A, B, C = 1'-4'); 6 precingulars (2, 3, 4, 5, 6, and li = 1"-6"); 6 cingulars (au, b, c, d, e, and fi = lc-6c); 6 sulcals (ai, fu, Ii, Im, Iu and Z = as, ras, rs, ls, 1 "' and ps); 5 postcingulars (II, III, IV, V, and VI = 2"'-6"'); 1 posterior intercalary (X = lp); and 1 antapical (Y = 1""). In Kofoidian terms the paratabulation formula is: lpr, 4', 6", 6c, 6s, 5"' 1 p, 1"". The paratabulation pattern is characterized by an L-type ventral configuration. Apical paraplates A and B (4' and 2') are in contact dorsal to P; Q is not present. Paraplates lu and li ( 1 ' and 6") are in contact in the ventral region (li is camerate and also contacts A; ai is planate). Paraplates lu and A are elongate, and a porichnion can be observed with the SEM on the edge of lu adjacent to the lu/A parasuture (Plate 2, fig. 3). In the sulcal region, most specimens of Carpatella exhibit a configuration in which paraplate ai (as) contacts II (2"'), but Iu ( 1 "') does not contact au (lc); thus Iu is not a postcingular paraplate (in the strict Kofoidian sense) because it does not contact the paracingulum. The length of the ai/II (as/2"') contact is variable (see Plate 1, figs. 1, 4; Plate 2, figs. 2, 6; Text-Figure 3A), and several specimens were observed with a four-way contact between paraplates ai, II, Iu and au. In contrast, most species having a Ventriosum pattern are characterized by a contact between paraplates Iu and au. In Carpatella, as in other species having the Ventriosum pattern, Iu and II are relatively small, the remaining postcingular paraplates (III-VI or 3"'- 6"') are distinctly larger. Postcingular parasuture IV/V is offset to the left of precingular parasuture 4/5, but does not attain a truly mid-dorsal position. Antapical paraplate Y (1"") is slightly asymmetrical-oblong, contacting paraplates X (lp), Z (ps) and III-VI (3"'-6"'). Antapical parasutures Y/X, Y/Z and Y/VI are relatively short, and may be nearly co-linear. Parasuture Y/V is only slightly longer than Y/III (see Helenes, 1986, p. 78-79).
Remarks:
Carpatella is not alone in having six sulcal and only five postcingular paraplates (speaking in the strict Kofoidian sense). The ai/II contact which eliminates Iu from the ranks of the postcingular paraplates, also occurs in all species assigned to Ctenidodinium, Leptodinium, Occisucysta, Tehamadinium and Korystocysta, in Gonyaulacysta dualis (Helenes, 1986), and in several species of Hystrichokolpoma (Damassa et al., 1987). Neotype. The specimen designated as the neotype of Carpatella cornuta is that illustrated in Plate 1, figs. 1, 4, 7: Amoco Production Company Locality No. 6720, C. Limhamn, southwestern Sweden, sample P 44601, slide A01, R 15.4, + 9.9. Designation of a neotype is appropriate in cases where the holotype and all other type material is missing (ICBN, 1983, Art. 7.8; see discussion). The neotype is stored at Amoco Production Company Research Center, Tulsa, Oklahoma. Comparison. At present Carpatella is a monotypic genus. It has been distinguished from Apteodinium, which is similar in overall appearance (e.g. shape, wall texture, size), on the basis of the presence of both apical and antapical horns (Stover and Evitt, 1978, p. 144). In addition, species of Apteodinium tend to lack clear evidence of paratabulation (Stover and Evitt, 1978); however, see Lucas-Clark (1987) for a partial Aptiana-Ventriosum paratabulation scheme. It is apparent that Carpatella cornuta possesses features of paratabulation, archeopyle and wall structure nearly identical to species of Cribroperidinium (Helenes, 1984). The two genera may be distinguished on the basis of the development of a second (antapical) horn in Carpatella and in the morphologic details by which the paratabulation is expressed (parasutural furrows and intratabular "pits" in Carpatella, parasutural ridges and intratabular ridges in Cribroperidinium). The only difference in paratabulation observed between these genera is in the configuration of the ai/ II-Iu/au contacts (Iu/au in Cribroperidinium, ai/II in most specimens of C. cornuta).
Discussion: (p. 174,175):
Since Grigorovich's original description of Carpatella cornuta in 1969, there have been relatively few occurrences reported in the literature. Specimens illustrated by Morgenroth (1968, p. 542- 544, pl. 44, figs. 1-3) and Evitt (1973, p. 34, pl. 1, figs. 12-14) were identified as "Danea mutabilis." Other occurrences reported as Carpatella cornuta include those by Hansen (1977, pl. 7, fig. 2 lF; 1979, p. 137, fig 5), Hultberg (1985, p. 61, pl. 1, figs. 3, 4, p. 112, pl.2,fig.C; 1986,p.38,pl. 1,figs.3,4),and Firth (1987, pl. 3, fig. 6). I am certain that Hansen's, Hultberg's and Firth's specimens are conspecific with my material, and am reasonably confident of the identification of Morgenroth's and Evitt's specimens as C. cornuta; however, I have serious doubts regarding the identity of those specimens described as C. cornuta by Fechner and Mohr (1986, p. 181-188, figs. 2, 3). Although their description corresponds fairly well in general terms to my concept of Carpatella, there are several differences in details of morphology and paratabulation between their specimens and those described here (see Fechner and Mohr, 1986, fig. 3). The apical horn is described as having formed from four apical parasutural crests, in contrast to the simple structure illustrated here. Also, the denticulate crests ("Kamme") noted by Fechner and Mohr (1986, p. 184) have not been reported in other specimens assigned to Carpatella, and are certainly not evident in the material used in this study. The paratabulation differs in the Moroccan material as follows: apical lu (1') is longer, and ai (as) is shorter than in specimens from Scandinavia; X (1 p) and Z (ps) do not show the arcuate shape typical of Cribroperidinium and its allies; there is no contact shown between ai (as) and II (2"'); no contact is shown between A (4') and B (2') dorsal to P (pr). Finally, the stratigraphic position of their specimens is anomalous, as C. cornuta previously has been reported only from Danian deposits. There is some question as to whether the material used in the present study is conspecific with the specimens described by Grigorovich in 1969, because neither I nor other authors (to my knowledge) have seen the holotype or other type material of C. cornuta. Indeed, it may be that no one knows what Carpatella cornuta really is! Comparison of the Scandinavian material with Grigorovich's illustrations (1969, figs. 1-6) demonstrates a general morphologic correspondence between the two, but details of paratabulation and other features cannot be determined with confidence. J. K. Lentin (oral commun., 1986) stated that she tried to locate the type specimen or other type material while she was in the Soviet Union, but was unsuccessful. If a holotype is missing, and additional type material is unavailable, it is appropriate to designate a neotype, which then serves as the type "as long as all of the material on which the name of the taxon is based is missing" (ICBN, 1983, Art. 7.8). Should the holotype or other type material be recovered, the neotype would no longer be needed. (Or, if the material described here is not identical to the original type material, a new name would be required for the Scandinavian material.) Many specimens of Carpatella correspond exactly to the synopsis and description of Cribroperidinium published by Helenes (1984) - even in possession of intratabular structures (Plate 3, fig. 1). The nearly complete morphologic overlap between the two genera presents a strong case for consideration of Carpatella as a junior synonym of Cribroperidinium. Both Helenes (1984) and Damassa (1984) argued that paratabulation should be considered before other aspects of cyst morphology in generic and suprageneric classification. The minor difference in paraplate configuration between Cribroperidinium and Carpatella (involving contacts of paraplates ai, II, Iu and au = as? 2"', 1"' and lc) does not imply a fundamental difference in paraplate topology; but instead (considering the high degree of mobility characteristic of paraplates in the sulcal region), may be seen as an interspecific or intergeneric variable. Note that in the specimen designated as the neotype (Plate 1, figs. 1, 4, 7), the ai/II contact is extremely short, while in other specimens (e.g. Plate 2, fig. 2) it is noticeably longer. In other aspects of morphology, Carpatella can be distinguished from Cribroperidinium only by the presence of an antapical horn and in the morphologic expression of features of paratabulation--features which for many other genera would be considered at the specific level. Despite the obvious similarities between C. cornuta and species of Cribroperidinium, it seems preferable to designate a neotype and retain C. cornuta as a separate (though isolated) species until the questions regarding the holotype are resolved. Regardless of the eventual taxonomic placement of Carpatella cornuta, the species remains an easily recognized and, geologically speaking, short-lived form a "Shakespearean rose" and a biostratigrapher's delight.
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Stratigraphic and Geographic Range:
The samples included in this study range in age from zone NP 1 to NP 3 (Danian). C. cornuta originally was described from Danian deposits in the Carpathian Mountains (Grigorovich, 1969). Additional occurences of C. cornuta have been reported from sediments of Danian age in Scandinavia (Morgenroth, 1968 [as Danea mutabilis]; Hansen, 1977, 1979; Kjellstrom and Hansen, 1981; Damassa, 1985; Hultberg, 1985, 1986), North America (Evitt, 1973 [as Danea mutabilis]; Firth, 1987) and Tunisia (Damassa, unpubl. observations). The Eocene occurrence in South Morocco reported by Fechner and Mohr (1986), if valid, is the first known occurrence of this species above the Danian (see discussion). C. cornuta has also been recorded from presumably uppermost Maastrichtian sediments, i.e., it occurs with Palynodinium grallator Gocht 1970 (an uppermost Maastrichtian form; Hansen, 1977) in the top Maastrichtian sample at W. Limhamn and in the Stevns Klint at Hojerup (Damassa, unpubl. observations). (Unfortunately, the Maastrichtian specimens of Carpatella are not well preserved-there remains some doubt as to their identity.) Hansen (1977) and Hultberg (1985, 1986), who also studied Scandinavian material, did not report a co-occurrence of these species. Firth (1987) depends on the separate occurrences of C. cornuta and P. grallator to determine the location of the Maastrichtian-Danian boundary in the southeastern United States. It may be that these species occur together only in stratigraphically complete sections, or that reworking of P. grallator has occurred in the sections used in this study.
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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.
Carpatella cornuta Grigorovich, 1969a, emend. Fechner and Mohr, 1986, emend. Damassa, 1988. According to Damassa (1988), this is a proximate cyst, subspherical to ellipsoidal with a short horn at the apex and antapex. Sexiform gonyaulacacean tabulation indicated by parasutural features. Ventral organization L type. No Q plate. 1"’ and 2"’ are relatively small. 1"’ does not contact the 1c plate. 1p and ps are elongate arcuate, 1"” is slightly asymmetrical oblong; 4"’/5"’ suture offset. Wall consists of autophragm only, outer part densely fibrous or spongy, inner surface smooth. Porichnion visible between apical paraplates. Archeopyle is precingular resulting from the loss of the 3" paraplate.
Size: length including horns 100-130 µm, width 90-100 µm.