Cryptonella sp. 2
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publication ID |
https://doi.org/ 10.4202/app.2010.0106 |
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persistent identifier |
https://treatment.plazi.org/id/03BB9544-FF85-A652-FF7F-F97C9FEEFE3F |
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treatment provided by |
Felipe |
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scientific name |
Cryptonella sp. 2 |
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Fig. 34C, G, I View Fig .
Material.—Two incomplete dorsal valves and one fragment of ventral valve from sample MH1.
Remarks.—Among the terebratulidine material there are several fragmentary specimens which resemble the form described above, especially in the internal structure of both valves, but they differ noticeably from Cryptonella sp. 1 in having proportionally wider shell ( Fig. 34C, G, I View Fig ). It may also represent a species of the genus Cryptonella .
Cryptonellinae gen. et sp. indet.
Fig. 34H, K View Fig .
Material.—Several fragments of single valves from samples MH1 and MH2, some of them with fragmentarily preserved internal details.
Remarks.—A few specimens from the sample MH−1 are distinguished by wider shell, unsupported and divided hinge plates. They resemble internally some Pseudodielasmatidae but the lack of the inner hinge plates may be caused by an incomplete preservation of these very fragile structures.
Specimens of uncertain affinity
Fig. 35 View Fig .
Remarks.—There are two groups of specimens in the investigated material which, for the time being, remain as unassigned to any known genus and species. The first group includes fragments of disarticulated valves or shells which are too incomplete to preserve diagnostic futures enough for reliable taxonomic determination. The other group, although consists of well preserved single valves and complete shells, represents juvenile stages of growth and are too immature to reveal reliable diagnostic characters of adults.
Among the first group of the fragmentary specimens mentioned above there are several broken dorsal and ventral valves which show well preserved internal structure but cannot be assigned to any species from the Muhua Formation. Some of these specimens are illustrated on Fig. 35O–U View Fig . The illustrated dorsal valves show well developed, deep and apparently uncovered septalium, long and high median septum, and absence of cardinal process. The interior of two ventral valves show the presence of thin but long, ventrally convergent dental plates. It seems probable that these specimens represent some camarotoechioid or pugnacoid rhynchonellides.
Several small−sized specimens, ranging from less than one to a few mm in width, represent the other group of forms difficult to determined taxonomically. Some of them represent adult micromorphic brachiopods and have been recently studied in detail ( Sun et al. 2004a; Baliński and Sun 2005,
http://dx.doi.org/10.4202/app.2010.0106
2008), but others evidently are juvenile stages of large adults. The latter are most numerous in sample MH1 (see Fig. 35A–N View Fig ). A shortage of specimens representing transitional growth stages makes impossible their reliable taxonomic assignment but it is highly probable that they represent one or more athyridide species co−occurring in the assemblage.
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