Back
Gerlachidium
From Williams et al., 2017:
[Gerlachidium, Benedek and Sarjeant, 1981, p. 338, 340
Type species: originally as Lejeunia aechmophora, Benedek, 1972 (pl.5, fig.7; text-fig.17)] ; Gerlachidium aechmophorum, Benedek and Sarjeant, 1981
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Benedek and Sarjeant, 1981]:
Diagnosis:
Cysts proximate, rounded pentagonal to compressed peridinioid, typically with a short apical horn or apical prominence and with two antapical
projections or horns. Paracingulum bounded, and paratabulation elsewhere indicated, by sutural or penitabular structures, linear or arcuate but not forming continuous crests. Surface of phragma between processes laevigate or with minor ornamentation.
Archeopyle formed by the opening of a single intercalary paraplate (Type l): the operculum typically remains attached and may close.
Affinities:
Gerlachidium differs from Lejeunecysta in its penitabular ornament; from Wetzeliella Eisenack, 1938, in being proximate, not cavate, and in lacking lateral horns; and from Areoligera Lejeune-Carpentier, 1938, emend. Williams and Downie, 1966, and the contemporary genera Chiropteridium Gocht, 1960, and Membranophoridium Gerlach, 1961, emend. Stover and Evitt, 1978, in having an intercalary, not an apical, archaeopyle and in the nature and distribution of the structures reflecting (incompletely) its paratabulation.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Modified description:
Stover and Williams, 1987, p. 105:
Synopsis:
Cysts proximochorate, autocyst outline compressed peridinioid to roundly pentagonal; surface with discrete, short, parasutural or penitabular processes arranged in linear or arcuate rows, but not arising from ridges or crests; archeopyle intercalary, type Ia or possibly I.
Description:
Shape: Compressed peridinioid to roundly pentagonal; horns typically short.
Wall relationships: Autophragm only.
Wall features: Isolated processes (not connected proximally or arising from ridges or crests) arranged as linear or arcuate parasutural or penitabular features.
Archeopyle: Intercalary, typically type la, adnate adcingularly; possibly I (2a only).
Paratabulation: Stated as simply being indicated; formula not given.
Paracingulum: Expressed by a shallow, transverse indentation bordered by discontinuous crests with serrate to spinate edges.
Parasulcus: Broad, featureless area on the ventral surface may reflect the parasulcus.
Size: Intermediate, length about 55 µm to 75 µm.
Affinities:
Gerlachidium differs from Lejeunecysta Artzner and Dörhöfer 1978 in having processes, and from Apectodinium (Costa and Downie 1976) Lentin and Williams 1977 and Wetzeliella Eisenack 1938 emended Lentin and Williams 1976 in lacking cavation.
[Gerlachidium, Benedek and Sarjeant, 1981, p. 338, 340
Type species: originally as Lejeunia aechmophora, Benedek, 1972 (pl.5, fig.7; text-fig.17)] ; Gerlachidium aechmophorum, Benedek and Sarjeant, 1981
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Original description: [Benedek and Sarjeant, 1981]:
Diagnosis:
Cysts proximate, rounded pentagonal to compressed peridinioid, typically with a short apical horn or apical prominence and with two antapical
projections or horns. Paracingulum bounded, and paratabulation elsewhere indicated, by sutural or penitabular structures, linear or arcuate but not forming continuous crests. Surface of phragma between processes laevigate or with minor ornamentation.
Archeopyle formed by the opening of a single intercalary paraplate (Type l): the operculum typically remains attached and may close.
Affinities:
Gerlachidium differs from Lejeunecysta in its penitabular ornament; from Wetzeliella Eisenack, 1938, in being proximate, not cavate, and in lacking lateral horns; and from Areoligera Lejeune-Carpentier, 1938, emend. Williams and Downie, 1966, and the contemporary genera Chiropteridium Gocht, 1960, and Membranophoridium Gerlach, 1961, emend. Stover and Evitt, 1978, in having an intercalary, not an apical, archaeopyle and in the nature and distribution of the structures reflecting (incompletely) its paratabulation.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Modified description:
Stover and Williams, 1987, p. 105:
Synopsis:
Cysts proximochorate, autocyst outline compressed peridinioid to roundly pentagonal; surface with discrete, short, parasutural or penitabular processes arranged in linear or arcuate rows, but not arising from ridges or crests; archeopyle intercalary, type Ia or possibly I.
Description:
Shape: Compressed peridinioid to roundly pentagonal; horns typically short.
Wall relationships: Autophragm only.
Wall features: Isolated processes (not connected proximally or arising from ridges or crests) arranged as linear or arcuate parasutural or penitabular features.
Archeopyle: Intercalary, typically type la, adnate adcingularly; possibly I (2a only).
Paratabulation: Stated as simply being indicated; formula not given.
Paracingulum: Expressed by a shallow, transverse indentation bordered by discontinuous crests with serrate to spinate edges.
Parasulcus: Broad, featureless area on the ventral surface may reflect the parasulcus.
Size: Intermediate, length about 55 µm to 75 µm.
Affinities:
Gerlachidium differs from Lejeunecysta Artzner and Dörhöfer 1978 in having processes, and from Apectodinium (Costa and Downie 1976) Lentin and Williams 1977 and Wetzeliella Eisenack 1938 emended Lentin and Williams 1976 in lacking cavation.