588
Journal of Paleontology 92(4):577–595
Table 5. Descriptive statistics of Streblotrypella sp. (5 colonies). Measure- ments and abbreviations as in Table 1.
Branch width Exozone width Endozone width Aperture width
N X SD CV MIN MAX 3 0.78 0.120 15.47 0.66 0.90
Aperture spacing along branch 2 0.48 0.035 7.44 0.45 0.50 Aperture spacing diagonally Metazooecia width
3 0.21 0.086 41.72 0.13 0.30 3 0.36 0.127 35.07 0.28 0.51 8 0.14 0.025 18.13 0.10 0.17
3 0.29 0.017 5.97 0.27 0.30 16 0.05 0.011 22.47 0.03 0.07
Trizna, 1958 from the Mississippian of Siberia and Europe in having 2 or 3 metazooecia between autozooecial apertures instead of 2–4in S. strabona, as well as in having thinner branches (branch width 0.66–0.90mm vs. 1.0–1.13mm in S. strabona). The present material, however, is insufficient for establishing a new species.
Family Goldfussitrypidae Gorjunova, 1985 Genus Nicklesopora Bassler, 1952
Type species.—Rhombopora elegantula Ulrich, 1884, by sub- sequent designation (Bassler, 1952). Lower Mississippian; Kentucky, USA.
Diagnosis.—Branched colonies. Axial region formed by few axial zooecia, not in distinct bundle. Autozooecia initially polygonal, irregular in transverse section, becoming hexagonal. Autozooecial apertures oval, arranged in regular alternating longitudinal rows. Single short, commonly massive superior hemiseptum near zooecial bend. Diaphragms rare. Paurostyles common, usually in single linear series enclosing apertures in polygonal patterns. Monticules rare, consisting of one much enlarged polymorph, surrounded by smaller polymorphs.
Occurrence.—Devonian–Permian; Eurasia and North America.
Remarks.—Nicklesopora differs from Rhabdomeson Young and Young, 1874 in its development of several axial zooecia instead of a single one and in the presence of only paurostyles instead of acanthostyles and paurostyles in Rhabdomeson. Nicklesopora differs from Paranicklesopora Gorjunova, 1988 in possessing only superior hemisepta and paurostyles (superior and inferior hemisepta are present in Paranicklesopora, as are acanthostyles and paurostyles).
Nicklesopora exigua (Ulrich, 1890) Figure 7.3–7.5
1890 Rhombopora exigua Ulrich, p. 651, pl. 70, fig. 10–10a. 1953 Rhombopora exigua; Nekhoroshev, p. 147, pl. 21, figs. 4a–c.
1962 non Rhombopora exigua Ulrich, 1890; Sakagami, p. 238, pl. 38, figs. 1–2.
Holotype.—ISGS (ISM) 4450, Burlington Group, Mississippian; Burlington, Iowa, USA.
Occurrence.—Upper Tournaisian, Mississippian; Kazakhstan. Burlington Limestone, Osagean, Mississippian; Iowa, USA.
Andrecito Member, Lake Valley Formation, Mississippian (Osagean); Sierra County, New Mexico, USA (present paper).
Description.—Branched colony, 0.85mm in diameter, with 0.45mm wide endozone and 0.20mm wide exozone. Auto- zooecia tubular, growing from central bundle of zooecia, abruptly bending in exozones. Superior hemisepta long, hook- shaped, curved proximally. Autozooecial diaphragms present. Autozooecial apertures oval, arranged in regular diagonal rows on branches, 0.05–0.06mm wide. Paurostyles abundant, 0.02–0.03mmin diameter. Autozooecial walls finely laminated, 0.003–0.005mm thick in endozone, laminated, with dark dividing layer in exozones.
Material.—NMMNH P-79588.
Remarks.—Nicklesopora exigua differs from N. varians (Ulrich, 1890) from the Mississippian of the USA in having thinner branches (branch diameter 0.85mm vs. 2–4mm in N. varians). Nicklesopora exigua differs from N. ispaiensis Balakin, 1975 from the lower Viséan of Uzbekistan in having thinner branches (branch width 0.85mm vs. 1.25–1.50mm in N. ispaiensis) and smaller apertures (aperture width 0.05–0.06mm vs. 0.07–0.09mm in N. ispaiensis).
Remarks.—The species described by Sakagami (1962) as Rhombopora exigua Ulrich, 1890 from the Mississippian of Japan does not fit the diagnosis of this species because it possesses two kinds of styles—acanthostyles and apparently paurostyles—as well as both superior and inferior hemisepta. The Japanese material could belong to the genus Paranicklesopora.
Family Nematotrypidae Spjeldnaes, 1984 Genus Clausotrypa Bassler, 1929
1971 Nemacanthopora Termier and Termier, p. 21.
Type species.—Clausotrypa separata Bassler, 1929, by original designation. Lower Permian; Timor, Indonesia.
Diagnosis.—Branched colonies. Autozooecia elongated-tubular with rare diaphragms. Autozooecial apertures rounded or oval. Tectitozooecia common, irregular, closed by laminated skeleton near colony surface. Acanthostyles on surface common. Auto- zooecial walls laminated, with dark serrated boundaries.
Occurrence.—Mississippian–Permian; Europe and Asia.
Remarks.—Clausotrypa differs from Nematotrypa Bassler, 1911 in the absence of hemiphragms and the budding pattern of the autozooecia, which bud from a distinct median axis in Nematotrypa. Nemacanthopora was separated from Clausotrypa because of the shape of its autozooecia (shorter vs. longer autozooecia in Clausotrypa). However, this character is quite subjective and inconsistent within species placed in both genera and apparently depends on the branch diameter. Therefore, Nemacanthopora was assigned as a junior synonym of Clausotrypa (Ernst et al., 2015).
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