. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. Fig. 13. A-B. Anisoceras armatum (J. Sowerby), USNMNH 236934. C-D. Anisoceras perarmatum Pictet & Campiche, USNMNH 236931. x 1. Material Twenty-seven specimens, SAM-PCA2940, 2950, 2956, 3115, 3122, 3143, 3148, 3152, 3193, 3214, 3243, 3283, 3285, 3299, 3339, 3352, 3355, 3358, 3361 and 3391, all from Egito, SAM-PCA4801, 4804 from Cabo Ledo and USNMNH 236928-29, 236931, 236933, 236940, and 236944 from Porto Amboim, either retaining recrystallized shell or preserved as composite internal moulds. Desc
. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. Fig. 13. A-B. Anisoceras armatum (J. Sowerby), USNMNH 236934. C-D. Anisoceras perarmatum Pictet & Campiche, USNMNH 236931. x 1. Material Twenty-seven specimens, SAM-PCA2940, 2950, 2956, 3115, 3122, 3143, 3148, 3152, 3193, 3214, 3243, 3283, 3285, 3299, 3339, 3352, 3355, 3358, 3361 and 3391, all from Egito, SAM-PCA4801, 4804 from Cabo Ledo and USNMNH 236928-29, 236931, 236933, 236940, and 236944 from Porto Amboim, either retaining recrystallized shell or preserved as composite internal moulds. Description Whorl section varies from almost circular in specimens replaced by calcite to slightly elliptical in those crushed individuals preserved as composite internal moulds. Ornament comprises small dorsolateral to lateral tubercles and the septate bases of prominent ventrolateral spines, between which strong ribs are looped in pairs. There are sporadic non-tuberculate intercalatories between looped ribs. The main ribs are also looped across the venter, and split into fine riblets, thirteen per three dorsolateral tubercles, on the dorsum. On the body chamber there may be one to two simple ribs (SAM-PCA3143, 3148) between looped ribs, whilst on the final shaft of USNMNH 236940, the button-and-loop ribbing is lost, and all ribs become single. Discussion Amongst contemporaneous species of Anisoceras, only A. saussureanum and A. armatum closely approach this species. Differences are noted under the discussion of A. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original South African Museum. Cape Town : The Museum
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectnaturalhistory, booky
