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Cauca
From Fensome et al., 2019:
Cauca, Davey and Verdier, 1971, p.14.
Taxonomic senior synonym: Hystrichodinium, according to Below (1981b, p.120–121) -- however, Lentin and Williams (1985, p.48) retained Cauca.
Type: Alberti, 1961, pl.9, fig.4, as Hystrichodinium parvum.
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Original description: [Davey and Verdier, 1971]:
Description:
Simple spherical to subspherical cyst without polar structures. Cingulum typically present; other tabulation, when present, defined by low crests. Spines long and simple. Archeopyle epitractal.
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Modified description:
Stover and Evitt, 1978, p. 202:
Synopsis:
Cysts skolochorate, acavate; body ovoidal to ellipsoidal with long simple processes; combination archeopyle, Type tAtP.
Description:
Shape: Body ellipsoidal to ovate; when the latter, narrow end is apical.
Wall relationships: Apparently two-layered; thin periphragm forms processes and is appressed to thicker endophragm; acavate.
Wall features: Low, possibly parasutural ridges present between processes. Processes long, simple, hollow, closed distally, and probably gonal. Periphragm smooth; endophragm smooth to finely tuberculate.
Paratabulation: Obscure, possibly defined by low parasutural ridges between processes; formula unknown.
Archeopyle: Combination epicystal archeopyle, Type tAtP; operculum free; constituent paraplates not delimited.
Paracingulum: Weakly to strongly marked by parallel transverse ridges located nearer the apical than the antapical end; epicyst noticeably smaller than hypocyst.
Parasulcus: Not indicated.
Size: Small to intermediate.
Affinities:
Cauca differs from Biorbifera in having widely separated, long, simple processes with rather numerous short projections. It differs Dorocysta in having a combination archeopyle rather than an apical one, and in having processes that are not confined to polar areas.
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Emended description Duxbury, 2024
Type: Alberti 1961, pl. 9, fig. 4, as Hystrichodinium parvum.
Emended diagnosis: Small, spherical, ellipsoidal to ovoidal cysts with the epicyst equal to or shorter than the hypocyst. The epicyst is rounded triangular in outline, extending into a low apical prominence and the hypocyst outline is semicircular. The endophragm is smooth, scabrate or granular and bears sutural crests marking an apparently gonyaulacoid tabulation and a clear cingulum. Crests usually bear numerous processes. The archeopyle is epicystal, with the operculum normally attached.
Remarks: In their comments on this genus, Davey and Verdier (1971, p. 14) concluded that, "The combination of epitractal archaeopyle and long sutural spines distinguish this genus from all previously described ones", and this approach was followed by Duxbury (2023). However, Davey and Verdier's generic diagnosis also stated "cyst without polar structures" and , "Spines long and simple". Other features which appear to be typical of Cauca are its relatively small size and a low apical prominence. Although the latter feature was specifically excluded from Davey and Verdier's generic diagnosis (op. cit., p. 14), two of the specimens that they assigned to Cauca parva (Alberti 1961) Davey and Verdier 1971 (op. cit., pl. 1, figs. 7 and 9) appear to show it. Cauca perplexa Duxbury 2023 has long, flat, flexuous, processes which are very complex distally, furcating three or four times, a feature unusual for this genus and again contrary to Davey and Verdier's generic diagnosis. Also, Cauca redacta n. sp. possesses low sutural crests which may or may not bear short, flexuous spines, whilst retaining other features typical of Cauca, including its small size and an apical prominence. In order to encompass the wide range of morphological variation now apparent within this genus, as exhibited by Cauca parva (Alberti 1961) Davey and Verdier 1971, C. maculosa Duxbury 2018, C. perplexa Duxbury 2023, C. rigida Duxbury 2023 and C. redacta n. sp., it has been necessary here to extend Davey and Verdier's concept of this genus.
Duxbury (2023, p. 130) referred to the similarity of the long, bladelike processes of some species of Cauca to those in Hystrichodinium Deflandre 1935, citing an epicystal archeopyle as definitive of Cauca, contrary to Below (1981, p. 120-121). Comparisons might also be made between Cauca redacta n. sp. (very reduced spines or none at all) and Heslertonia Sarjeant 1966b, particularly as some representatives of Heslertonia have significantly reduced crestal height and sometimes very short crestal spines (see Heslertonia inferior n. sp., below). In this case it seems to be the relatively small size and rounded-triangular epicyst with a low apical prominence in Cauca that sets them apart. Also, there seems to be a continuum in C. redacta from specimens with numerous distinct (but short) sutural spines to those with none.
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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.
Cauca Davey and Verdier, 1971. According to Davey and Verdier (1971, p.14), this is a simple, spherical to subspherical cyst without polar structures. Cingulum is typically present. Other tabulation, when present, defined by low crests. Spines long and simple. Archeopyle epitractal.
Cauca, Davey and Verdier, 1971, p.14.
Taxonomic senior synonym: Hystrichodinium, according to Below (1981b, p.120–121) -- however, Lentin and Williams (1985, p.48) retained Cauca.
Type: Alberti, 1961, pl.9, fig.4, as Hystrichodinium parvum.
---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Davey and Verdier, 1971]:
Description:
Simple spherical to subspherical cyst without polar structures. Cingulum typically present; other tabulation, when present, defined by low crests. Spines long and simple. Archeopyle epitractal.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Modified description:
Stover and Evitt, 1978, p. 202:
Synopsis:
Cysts skolochorate, acavate; body ovoidal to ellipsoidal with long simple processes; combination archeopyle, Type tAtP.
Description:
Shape: Body ellipsoidal to ovate; when the latter, narrow end is apical.
Wall relationships: Apparently two-layered; thin periphragm forms processes and is appressed to thicker endophragm; acavate.
Wall features: Low, possibly parasutural ridges present between processes. Processes long, simple, hollow, closed distally, and probably gonal. Periphragm smooth; endophragm smooth to finely tuberculate.
Paratabulation: Obscure, possibly defined by low parasutural ridges between processes; formula unknown.
Archeopyle: Combination epicystal archeopyle, Type tAtP; operculum free; constituent paraplates not delimited.
Paracingulum: Weakly to strongly marked by parallel transverse ridges located nearer the apical than the antapical end; epicyst noticeably smaller than hypocyst.
Parasulcus: Not indicated.
Size: Small to intermediate.
Affinities:
Cauca differs from Biorbifera in having widely separated, long, simple processes with rather numerous short projections. It differs Dorocysta in having a combination archeopyle rather than an apical one, and in having processes that are not confined to polar areas.
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Emended description Duxbury, 2024
Type: Alberti 1961, pl. 9, fig. 4, as Hystrichodinium parvum.
Emended diagnosis: Small, spherical, ellipsoidal to ovoidal cysts with the epicyst equal to or shorter than the hypocyst. The epicyst is rounded triangular in outline, extending into a low apical prominence and the hypocyst outline is semicircular. The endophragm is smooth, scabrate or granular and bears sutural crests marking an apparently gonyaulacoid tabulation and a clear cingulum. Crests usually bear numerous processes. The archeopyle is epicystal, with the operculum normally attached.
Remarks: In their comments on this genus, Davey and Verdier (1971, p. 14) concluded that, "The combination of epitractal archaeopyle and long sutural spines distinguish this genus from all previously described ones", and this approach was followed by Duxbury (2023). However, Davey and Verdier's generic diagnosis also stated "cyst without polar structures" and , "Spines long and simple". Other features which appear to be typical of Cauca are its relatively small size and a low apical prominence. Although the latter feature was specifically excluded from Davey and Verdier's generic diagnosis (op. cit., p. 14), two of the specimens that they assigned to Cauca parva (Alberti 1961) Davey and Verdier 1971 (op. cit., pl. 1, figs. 7 and 9) appear to show it. Cauca perplexa Duxbury 2023 has long, flat, flexuous, processes which are very complex distally, furcating three or four times, a feature unusual for this genus and again contrary to Davey and Verdier's generic diagnosis. Also, Cauca redacta n. sp. possesses low sutural crests which may or may not bear short, flexuous spines, whilst retaining other features typical of Cauca, including its small size and an apical prominence. In order to encompass the wide range of morphological variation now apparent within this genus, as exhibited by Cauca parva (Alberti 1961) Davey and Verdier 1971, C. maculosa Duxbury 2018, C. perplexa Duxbury 2023, C. rigida Duxbury 2023 and C. redacta n. sp., it has been necessary here to extend Davey and Verdier's concept of this genus.
Duxbury (2023, p. 130) referred to the similarity of the long, bladelike processes of some species of Cauca to those in Hystrichodinium Deflandre 1935, citing an epicystal archeopyle as definitive of Cauca, contrary to Below (1981, p. 120-121). Comparisons might also be made between Cauca redacta n. sp. (very reduced spines or none at all) and Heslertonia Sarjeant 1966b, particularly as some representatives of Heslertonia have significantly reduced crestal height and sometimes very short crestal spines (see Heslertonia inferior n. sp., below). In this case it seems to be the relatively small size and rounded-triangular epicyst with a low apical prominence in Cauca that sets them apart. Also, there seems to be a continuum in C. redacta from specimens with numerous distinct (but short) sutural spines to those with none.
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
G.L. Williams short notes on species, Mesozoic-Cenozoic dinocyst course, Urbino, Italy, May 17-22, 1999 - LPP VIEWER CD-ROM 99.5.
Cauca Davey and Verdier, 1971. According to Davey and Verdier (1971, p.14), this is a simple, spherical to subspherical cyst without polar structures. Cingulum is typically present. Other tabulation, when present, defined by low crests. Spines long and simple. Archeopyle epitractal.