CATALOG OF ORIGINAL DESCRIPTIONS: Guembelitria sergipensis Koutsoukos 1994
This page provides data from the catalog of type descriptions. The catalog is sorted alphabetically. Use the current identification link to go back to the main database.
Citation: Guembelitria sergipensis Koutsoukos 1994Taxonomic rank: speciesType specimens: 5791-IType age (chronostrat): Upper AptianType locality: Holotype is from a cutting sample of well I-CA-I (latitude 10’ 54‘ 30”S, longitude 37” 07’ 45” W; Fig. I), depth 1245-1260 m (upper Aptian). Taquari Member, Riachuelo Formation, Sergipe Basin, northeastern Brazil.Type repository: Rio de Janeiro, Departamento de Geologia e Paleontologia of the Museu Nacional
Original Description This species is characterized by having a minute trochoid test, triserial throughout, with a short, moderately high trochospire, and a slight variability during ontogeny in the maximum height/diameter (H/D) ratio (e.g., from H/D around 1.1, elongate-conical neanic to early ephebic morphotypes-Pl.1, figs.5, 6, 15, Pl.2, fig.2; and H/D close or equal to 1, nearly as broad as long, globular trochoid, early ephebic and gerontic morphotypes-Pl.1, figs.1-2, 8, 12, 13, Pl.2, figs.1, 3, 4). Three inflated, gradually enlarging globular chambers in the last whorl, distinct, differing little in size and comprising about 2/3 of the test size. Chambers of previous whorl are indistinct, mostly obscured by overgrowth of test surface calcification. Ultimate chamber in mature specimens has smoother ornamentation and partially covers the umbilicus (e.g., Pl.1, figs.1, 8, 12, 13). Umbilicus small, shallow; periphery rounded. Sutures distinct and depressed, in the last whorl; indistinct in the previous whorls. Aperture a low to medium sized umbilical arch at the base of the last formed chamber, slightly asymmetrical. The aperture is nearly completely obscured by overgrowths of test ornamentation and deposited calcite particles. Test surface covered with blunt rounded or elongate poreless pustules, some forming elongate imperforate quadrangles (= short ridges)-(Pl.1, figs.3, 4, 5, 7, 9-11 and Pl.2, figs.5, 9, 10), several pore mounds (pores of maximum diameter around 1.0 microns; see Pl.1, figs.11, 14, 16 and Pl.2, figs.7, 12), and sporadic presence of pores on edges of pustules (Pl.2, figs.5, 10). The specimens show an irregular development of the pore mounds on the first two chambers of the last whorl (Pl.1, figs.14, 16, and Pl.2, fig.5, 7). The ultimate chamber may be densely covered with small poreless pustules and totally lack pore mounds (Pl.2, fig.10), whereas these may have been sealed on the earlier chambers by shell overgrowths. Morphologically intermediate forms between G. sergipensis and G. cenomana (Keller), with a more elongate test (WD from around 1.2 to 1.3). higher trochospire, and more developed pore mounds surface texture, are recorded in the middle Albian to lowermost upper Albian (PI. 2, figs. 6-12). Thirteen paratypes are illustrated by the lateral views in PI. 1, figs. 5-16, and PI. 2, figs. 1-12. The overall morphological features are similar to that of the holotype, varying only slightly in the WD ratio, coarseness of the test surface ornamentation and in the density and regularity of pore mounds. Size: 184/182 µm Etymology: Guembelitria sergipensis derives its name from the type locality, the state of Sergipe. Extra details from original publication
Remarks: The new species has a distinctive short, moderately high trochospire, triserial coiling throughout, a short, almost symmetrical, low intraumbilical apertural arch, often masked, and a test surface covered by small rounded or elongate pustules, with several pore mounds. The triserial chamber arrangement and the test surface ornamentation are consistent with placement of the species in the genus Guembelitria Cushman. However, it differs from the later species of Guembelitria (e.g., G . cenomana (Keller) uppermost Albian to uppermost Turonian; G. cretacea Cushman Coniacian to lower Danian) chiefly in having a trochoid test (WD close or equal to 1), coarser pustulose surface ornamentation with poreless pustules, sparse occurrence of pore mounds, sporadic presence of pores on edges of pustules and indistinct chambers in the earlier whorls.
Deposition of types. The holotype and figured paratypes of Guembelitria sergipensis n. sp. are deposited as follows
Holotype: from well I-CA-I, depth 1245-1260 m, deposited in the microfossil collections of the Departamento de Geologia e Paleontologia of the Museu Nacional, Rio de Janeiro (Quinta da Boa Vista, s/no.-20942 Rio de Janeiro, RJ-Brazil). with the number 5792-1.
Paratype 1: from well I-CA-I, depth 1125-1140 m (cutting sample), deposited in the Protozoa collections of the Natural History Museum, London, with the number BMNH P52646.
Paratypes 2-3: deposited in the microfossil collections of the Departamento de Geologia e Paleontologia of the Museu Nacional. Rio de Janeiro, where the following numbers were allocated: Paratype 2, number 57934, from well I-CA-I, depth 1095-1110 m (cutting sample); Paratype 3, number 5794-1, from well I-CA-I. depth 1245-1260 m (cutting sample).
Paratypes 4-13 and figured type of G . cenomana (Keller): to be deposited in the Cushman Collection of Foraminifera at the National Museum of Natural History, Smithsonian Institution (Washington, D.C.).
References:
Koutsoukos, E. A. M. (1994). Early stratigraphic record and phylogeny of the planktonic genus Guembelitria Cushman, 1933. Journal of Foraminiferal Research. 24: 288-295. gs
Guembelitria sergipensis compiled by the pforams@mikrotax project teamviewed: 12-8-2026
These terms and conditions contain rules about posting comments. By submitting a comment, you are declaring that you agree with these rules:
Although the administrator will attempt to moderate comments, it is impossible for every comment to have been moderated at any given time.
You acknowledge that all comments express the views and opinions of the original author and not those of the administrator.
You agree not to post any material which is knowingly false, obscene, hateful, threatening, harassing or invasive of a person's privacy.
The administrator has the right to edit, move or remove any comment for any reason and without notice.
Failure to comply with these rules may result in being banned from submitting further comments.
These terms and conditions are subject to change at any time and without notice.
{"commentics_url":"\/\/www.mikrotax.org\/comments\/","page_id":1449895,"enabled_country":true,"country_id":0,"enabled_state":false,"state_id":0,"enabled_upload":false,"maximum_upload_amount":3,"maximum_upload_size":5,"maximum_upload_total":5,"captcha":true,"captcha_url":"https:\/\/www.mikrotax.org\/comments\/frontend\/index.php?route=main\/form\/captcha&page_id=1449895","cmtx_wait_for_comment":"cmtx_wait_for_comment","lang_error_file_num":"A maximum of %d files are allowed to be uploaded","lang_error_file_size":"Please upload files no bigger than %.1f MB in size","lang_error_file_total":"The total size of all files must be less than %.1f MB","lang_error_file_type":"Only image file types are allowed to be uploaded","lang_text_loading":"Loading ..","lang_placeholder_country":"Country","lang_placeholder_state":"State","lang_text_country_first":"Please select a country first","lang_button_submit":"Add Comment","lang_button_preview":"Preview","lang_button_remove":"Remove","lang_button_processing":"Please Wait.."}
Koutsoukos 1994 pl1 f1-4.JPG
Koutsoukos 1994 pl1 f1-4.JPG
Comments