Spiroplectammina spectabilis (Grzybowski, 1898), emend. Kaminski, 1984



Fig. 104-1. Five species of Spiroplecta described by Grzybowski (1898, 1901) here regarded as synonymous with S. spectabilis (redrawn from the type figures). 1. Spiroplecta brevis Grzybowski, 1898. 2. Spiroplecta spectabilis Grzybowski, 1898. Spiroplecta costidorsata Grzybowski, 1898. 4. Spiroplecta foliacea Grzybowski, 1898. 5. Spiroplecta clotho Grzybowski, 1901


ORIGINAL DESIGNATION: Spiroplecta spectabilis Grzybowski, 1898.

TYPE REFERENCE: Grzybowski, J., 1898, Otwornice pokładow naftonośnych okolicy Krosna. Rozprawy Wydziału Matematyczno-Przyrodniczego, Akademia Umiejętności w Krakowie, serya 2, vol. 33, p. 293, pl. 12, fig. 12. See also: Kaminski, M.A. 1984. Shape variation in Spiroplectammina spectabilis (Grzybowski). Acta Paleontologica Polonica, 29, 29-49.

TYPE SPECIMEN: Not originally designated. Numerous specimens from Grzybowski's samples are deposited in the micropaleontological collections of the Jagiellonian University, Kraków. Syntypes of Spiroplecta spectabilis preserved in the Grzybowski Collection of 1898 are registered as UJ-132-P, 1/82a. This slide contains three specimens, one of which corresponds to the type figure. Kaminski & Geroch (1993) designated this specimen the lectotype. An additional syntype of S. spectabilis labelled "Potok" is registered in slide UJ-132-P, 1/82b. Syntypes of Spiroplecta brevis are registered as UJ-132-P, 1/83a-e. Syntypes of Spiroplecta foliacea are registered as UJ-132-P, 1/84a. The type specimen of Spiroplecta costidorsata is registered as UJ-132-P, 1/85.

TYPE LEVEL: Paleogene, Silesian Unit of the Polish Carpathians.

TYPE LOCALITY: Not originally designated. Grzybowski reported Spiroplecta spectabilis from three exploration wells drilled in the vicinity of Krosno Poland. The lectotype is from the Potok H-33 well, 170 m. Syntypes of Spiroplecta brevis are from the Potok H-33 well, 170 m, 210 m, 227 m, and 15 m. Spiroplecta foliacea were described from an additional six wells. Syntypes in the collection are from the Potok H-40 well, 24 m, and from an outcrop sample labelled "Krościenko, red clay". The type specimen of Spiroplecta costidorsata is from the Potok H-26 well, 95 m.

DIAGNOSTIC FEATURES: Test free, initially planispiral, later biserial. In megalospheric forms, the planispiral portion consists of 4-7 chambers, and may be wider than the subsequent biserial portion. The planispiral portion of microspheric forms is minute in comparison, and may also be wider than the biserial part. Chambers in the biserial part are low and numerous. As many as 36 biserial chambers have been observed in microspheric individuals. In both generations, the biserial part is rhomboidal in cross-section and has nearly parallel sides, though in microspheric forms it normally increases in breadth initially and may decrease in breadth distally. Sutures are normally flush or depressed slightly. In the biserial part, sutures and inclined approximately 60° to the long axis of the test. Peripheral margin is acute, and may be dentate or weakly keeled. Wall is imperforate, finely agglutinated with a smooth surface. Forms living on pelagic substrates may agglutinate coccolith debris. Aperture is a narrow interiomarginal slit.

SIZE: Mean length varies from 0.35 to 1.25 mm. The lectotype of S. spectabilis is 0.20 mm x 0.55 mm.

SYNONYMS:
Spiroplecta brevis Grzybowski. Grzybowski, J., 1898, Rozpr. Wydz. Matemat.-Przyr., Akad. Umiej. Krakow, ser. 2, 33, p. 293, pl. 12, fig. 13.
Spiroplecta foliacea Grzybowski. Grzybowski, J., 1898, Rozpr. Wydz. Matemat.-Przyr., Akad. Umiej. Krakow, ser. 2, 33, p. 293, pl. 12, fig. 12.
Spiroplecta costidorsata Grzybowski. Grzybowski, J., 1898, Rozpr. Wydz. Matemat.-Przyr., Akad. Umiej. Krakow, ser. 2, 33, p. 294, pl. 12, fig. 11.
Spiroplecta clotho Grzybowski. Grzybowski, J., 1801, Rozpr. Wydz. Matemat.-Przyr., Akad. Umiej. Krakow, ser. 2, 41, p. 283, pl. 7, fig. 18.
Spiroplectoides clotho (Grzybowski). Cushman, J.A., & Jarvis, P.W., 1928, Contr. Cush. Lab. Foram. Res. 4, p. 101, pl. 14, fig. 13.
?Spiroplectoides eocenica Cushman & Barksdale. Cushman, J.A. & Barksdale, J.D., 1930, Contr. Stanford Univ. Geol. Dept. 1, p. 66, pl. 12, fig. 5a,b.
Spiroplectoides californica Cushman & Campbell. Cushman, J.A., & Campbell, A.S., 1934, Contr. Cush. Lab. Foram. Res. 10, p. 70, pl. 9, fig. 13-14.
Spiroplectammina mexiaensis Lalicker. Lalicker, C.G., 1935. Contr. Cush. Lab. Foram. Res. 11, p. 43, pl. 6, fig. 5-6.
Spiroplectoides directa Cushman & Siegfus. Cushman, J.A., & Siegfus, S.S., 1939. Contr. Cush. Lab. Foram. Res. 15, p. 26, pl. 6, fig. 7-8.
Spiroplectammina grzybowskii Frizzell. Frizzell, D.L., 1943. J. Paleontol. 17, p. 339, pl. 55, fig. 12a-13.
Spiroplectammina perplexa Israelsky. Israelsky, M.C., 1951. U.S. Geol. Surv. Prof. Paper 240-A. p. 12, pl. 3, fig. 9-14.
Spiroplectammina brunswickensis Todd & Kniker. Todd, R., & Kniker, H.T., 1952. Cush. Found. Foram. Res. Spec. Publ. 1, p. 6, pl. 1, fig. 16.

OBSERVED OCCURRENCES: Spiroplectammina spectabilis is one of the best known and widely distributed Paleogene species of deep-water agglutinated foraminifera. It was first described from the Paleogene of the Carpathian flysch (Grzybowski, 1898), and has been subsequently found in the Caucasus (Glaessner, 1937; Subbotina, 1950), Caribbean (Cushman & Jarvis, 1928), Tunisia (Aubert & Berggren, 1976), along the Pacific margin of North and South America (Cushman & Campbell, 1934; Todd & Kniker, 1952), in the Northwest Pacific (Serova, 1987; Kaiho, 1992), South Pacific and Papua New Guinea (Webb, 1975; Haig, 1982; Milner, 1997), New Zealand (Kaiho et al., 1996), South Atlantic (Widmark, 1997), and throughout the North Atlantic and North Sea provinces. In its type area, the first occurrence of this species marks the base of the Late Paleocene Spiroplectammina spectabilis Zone of Geroch & Nowak (1984). However, this event in the Polish Carpathians may reflect the immigration of the species, since it undoubtedly occurs in the Maastrichtian in Trinidad (Kaminski et al., 1988; Beckmann, 1994), in northeast Venezuela (Galea-Alvarez, 1985), on Sakhalin Island (Serova, 1987), and on Hokkaido (Kaiho, 1992). It is found in the Lower Paleocene of other areas of the Carpathians as well as in the Atlantic. Martin (1964) reported it as Spiroplectammina perplexa from the Lower Danian of the Moreno Formation in California. In the Romanian Eastern Carpathians, Ion (1995) recorded its FO in the G. eugubina Zone in the Lepsa Beds, and noted reports of it in the uppermost Maastrichtian of the Hangu Beds. Based on these occurrences, Ion (1995) argued for restricting the S. spectabilis Zone in the Romanian Carpathians to the interval between the LO of Rzehakina inclusa and the FO of Saccamminoides carpathicus.
At Caravaca Spain, the FO of S. spectabilis was observed within the K/T boundary clay layer (Coccioni & Galeotti, 1994). We have also observed a peak in S. spectabilis above the K/T boundary in deep-water limestones from Gubbio and from Sopelana Spain (Kuhnt & Kaminski, 1993; 1996). Peryt et al. (1997) observed the FO of S. spectabilis in Zone PO in flysch sediments of the Rotwandgraben section, Eastern Alps (Austria). At this locality its acme is in Zone P? to P1a. At ODP Site 959 in the equatorial Atlantic, its the FO of S. spectabilis is only centimeters above the K/T boundary, and it displays a prominent acme in the lower Danian (Fig. 104-2). We observed a similar peak in the Danian in one or two Labrador Shelf wells. This peak in the abundance of S. spectabilis following the K/T boundary event therefore appears to have a wide geographical distribution.


Fig. 104-2. Abundance variations of common DWAF across the K/T boundary interval at ODP Site 959 off the Ivory Coast. The early Danian acme in Spiroplectammina spectabilis has now been observed at several localities in the Atlantic and western Tethys, after Kuhnt et al. (1998)


In the Zumaya section of northern Spain, its first occurrence is near the base of Zone P4. In the northern areas of the North Atlantic, S. spectabilis can be abundant in sediments of Late Paleocene age. It displays a distinctive abundance maximum in the lower part of Upper Paleocene in the western Barents Sea. Its last common occurrence occurs near the base of the uppermost Paleocene tuff horizon in the North Sea and Barents Sea, and near the Paleocene/Eocene boundary along the Labrador Margin. Another acme in S. spectabilis has been found in the Contessa Road section near Gubbio within Zone NP9, just beneath the Paleocene/Eocene boundary carbon isotope excursion (Galeotti et al., 2000). The last occurrence of S. spectablis is generally within the Middle Eocene along the North Atlantic margins. However, at paleobathymetrically deeper localities it ranges into Upper Eocene. At ODP Site 647 in the Labrador Sea its LO coincides with the Eocene/Oligocene boundary as determined by nannofossils and magnetostratigraphy. Verdenius & Van Hinte (1983) used this species to determine the top of the Eocene in DSDP sites in the Norwegian-Greenland Sea. In a study of a paleobathymetric transect in the Central North Sea, Jones (1988) reported it as common in upper slope and basin plain assemblages but less common in the middle slope facies. In the Polish Carpathians its LO coincides with the base of the uppermost Eocene "Globigerina Marls".
Spiroplectammina spectabilis was largely restricted to flysch-type assemblages. It has not been found in DSDP/ODP assemblages from abyssal sites in the North Atlantic, except at high latitudes (Site 647), where it forms a distinctive acme in Zone NP17 (see Stratigraphy chapter). Its occurrence is rare and discontinuous in the Paleogene Scaglia Rossa of Italy, except at particular intervals. Its distribution suggests seems to be linked with the trophic continuum. It is extremely rare in the eastern Atlantic ODP sites (Kuhnt & Collins, 1996; Kuhnt & Urquhart, 2001). In the western Barents Sea, its maximum occurrence is observed in the middle part of the Paleocene, while in the Central North Sea it is most common in the upper Paleocene. Its occurrence in the deep-sea sites is most likely linked to elevated organic input and siliciclastic flux.

KNOWN STRATIGRAPHIC RANGE: Maastrichtian to latest Eocene.

BATHYMETRY: Bathyal to abyssal.

REMARKS: Spiroplectammina spectabilis may be one of the most widely recognized Paleogene species, since it figures prominently in a number of zonal schemes. This species may be considered as a plexus of forms that differ in length and thickness, with significant differences between end members (Kaminski, 1984). This variability has no doubt contributed to the multiplicity of available junior synonyms. The concept of Spiroplectammina spectabilis adopted here consists of no fewer than 11 validly described species.
Grzybowski described five species of Spiroplecta that we consider to be fully synonymous with S. spectabilis. Spiroplecta brevis and S. spectabilis are clearly megalospheric forms, while S. costidorsata, S. foliacea and S. clotho are microspheric individuals.
Four complete specimens of Spiroplecta brevis are preserved in the Grzybowski collections. In all cases, Grzybowski selected specimens that are comparatively short (4-5 pairs of biserial chambers) and possess an initial spire that is wider than the biserial part. It appears that Grzybowski himself may have had difficulty distinguishing S. spectabilis from S. brevis, since there are undifferentiated vials in his collection that are labelled as containing both forms.
Two specimens of Spiroplecta foliacea are preserved in the Grzybowski collections, but the complete specimen depicted in Grzybowski's pl. 12, fig. 12 appears to be missing. Both specimens appear to be wider than the one depicted in Grzybowski's type figure. The longest specimen is broken, and has 15 pairs of chambers. In our understanding, the type figure of S. foliacea depicts a rather narrow microspheric individual of Spiroplectammina spectabilis, whereas S. clotho is an abnormally wide specimen. The surviving specimen of Spiroplecta costidorsata preserved in the Grzybowski collection is a microsphaeric individual with 13 pairs of chambers. Unlike the type figure, the preserved syntype has parallel sides without any trace of lateral spines, as the name and the type illustration suggests.
In their studies of faunas from Trinidad, Mexico, and California, Cushman and co-workers used the designations Spiroplectoides clotho (Grzybowski) and S. spectabilis, but described three additional species from California: S. eocenica, S. californica and S. directa (Fig. 105-3). A fourth species from California was described by Israelsky (1951).
Spiroplectoides eocenica was described by Cushman & Barksdale (1930) from the Eocene Martinez Formation of the San Francisco area. Cushman & Barksdale reported that it "resembles Spiroplectoides clotho (Grzybowski), but the chambers are lower, the sides parallel, the sutures hardly if at all limbate, and the relative length of the test is very much less". The wall was described as being "distinctly perforate". We have discovered, however, that Cushman often mistook the fine agglutinated grains for perforations. Therefore we tentatively include this species as a synonym of S. spectabilis pending revision of the types.
Spiroplectoides californica was described by Cushman & Campbell (1934) from the Paleogene Chico and Moreno Formations. The species was described as "varying in thickness at the apertural end, which becomes as thick as broad". In comparison to specimens from Trinidad that Cushman had placed in S. clotho, the specimens from California were described as having chambers that are "not so low and broad as in the latter species, and the microspheric form is not so definitely lance-shaped". However, the type specimens of S. californica preserved in the Cushman Collection (CC21294 - CC21299) are not as thick as they are broad. The holotype is 0.28 mm in width and only 0.21 mm in thickness. The mean thickness of the five preserved type specimens is 0.91 ± 0.2 mm. The mean thickness of these specimens is not significantly different from virtual topotypes of S. spectabilis collected from the Polish Carpathians.


Fig. 104-3. Specimens of S. spectabilis from localities in the Americas illustrated by Cushman (1927, 1934), Cushman & Campbell (1934) and Cushman & Siegfus (1939), redrawn from Cushman's illustrations. 1-5. Specimens reported as "Spiroplectoides clotho". Specimen #3 is from the Velasco Shale of Mexico, others are from Trinidad. 6-7. Specimens reported as "Spiroplectoides spectabilis" by Cushman (1934). 8. Specimen reported as "Spiroplectoides eocenica" by Cushman & Barksdale (1930). 9-10. Specimens reported as "Spiroplectoides californica" by Cushman & Campbell (1934). 11-12. Specimens reported as "Spiroplectoides directa" by Cushman & Siegfus (1939)


Spiroplectoides directa was described by Cushman & Siegfus (1939) from the Middle to Upper Eocene Kreyenhagen Shale at Garza Creek, California. The species was described as having a thin, perforate, calcareous wall and a terminal aperture. The holotype (CC 25445) is apparently silicified with an agglutinated test, and the specimen is broken at its apertural end. This gives it the appearance of having a terminal aperture. The species was again reported by Cushman & Siegfus (1942) from the Kreyenhagen Shale type locality. Cushman & Renz (1948) later used this name for specimens from the Middle Eocene Navet Formation of Trinidad.
Spiroplectammina perplexa was described from the Middle Eocene Lodo Formation of California by Israelsky (1951), and later Martin (1964) used this term for his specimens form the Paleocene Moreno Formation. The test was described as being "smooth, minutely granular, with largely siliceous cement".
Israelsky placed the specimens described as S. clotho by Cushman (1934), Cushman & Jarvis (1928) and Cushman & Renz (1946) in the synonymy of his S. perplexa. The type specimens preserved in the Cushman Collection (USNM 560501 & USNM 560502: see fig. 115-4) are strongly compressed and decrease in width distally. The mean thickness of the two preserved specimens is only 0.07 mm. It is the thinnest end member of the named synonyms of S. spectabilis measured by Kaminski (1984). Such relatively thin forms have been given the name "S. spectabilis forma perplexa" by Kaminski (1984). Workers familiar with the species S. spectabilis from the North Sea region have noticed that the Eocene morphotype is apparently smaller and thinner than the Paleocene morphotype (e.g., King, 1989). Gradstein (1983) regarded the transition from robust Paleocene forms to thinner Eocene forms to reflect an evolutionary transition. We must point out, however, that flat, thin forms that are not significantly different in overall dimensions from the Eocene type specimens of S. perplexa are also found in the mid-Paleocene Moreno Shale of California. For this reason, Kaminski (1984) regarded this flattened morphotype as simply an ecophenotype of S. spectabilis, and assigned it an informal name (S. spectactabilis forma perplexa), following the practise of Feyling-Hansen (1972) for distinct ecophenotypic variants. However, Charnock & Jones (1990) regarded this form as being "no more than infrasubspecifically distinct from the typical form". It is possible that at least in the Paleocene, the paleobathymetric setting influences the shape of S. spectabilis, with the thicker, more robust forms occurring more frequently in deeper assemblages. Eocene topotype specimens from the Polish Carpathians, which are from undoubtedly deep-water assemblages, are significantly thicker (mean = 0.18 ± 0.3 mm) than the types of S. perplexa.
Spiroplectammina mexiaensis was originally described by Lalicker (1935) from the Mexia clay member of the Wills Point Formation in Mexia Co., Texas. Three slides of specimens are preserved in the Cushman Collection. The holotype (CC21924) is a megalosphaeric specimen, and because the test is white, not silicified, the exact arrangement of the early chambers is not visible. The biserial part consists of nine pairs of chambers with depressed sutures. The holotype is 0.6 mm in length and 0.22 mm in maximum width. The two paratypes housed in the collection (CC21925, USNM 371544) are also megalosphaeric forms. All of the megalosphaeric syntypes possess spiral parts that are narrower than the widest portion of the biserial part.
Two species of Spiroplectammina originally described from South America considered here to be junior synonyms of are S. grzybowskii Frizzell, and S. brunswickensis Todd & Kniker (Fig. 105-4). Frizzell (1943) originally described S. grzybowskii from ?Late Cretaceous of a well drilled near Negritos Peru (J.P. well 1755, 2310'). This fauna is in fact Danian in age (see remarks under Reticulophragmium garcilassoi). In his description of the species, Frizzell placed in synonymy the specimens from Lizard Springs illustrated by Cushman & Jarvis (1928) as S. clotho. Cushman (1947) later reported S. grzybowskii from additional localities in Trinidad and Venezuela, but remarked that its relationship to his S. clotho is "unclear". The paratypes of S. grzybowskii preserved in the Cushman Collection (CC39551 - CC39552) are relatively large in comparison to forms described from North America, but its dimensions are not significantly different from those of the topotype specimens of S. spectabilis from the Polish Carpathians.
The second South American species is S. brunswickensis, described by Todd & Kniker (1952) from the Upper Eocene Aqua Fresca Shale of southern Chile. Todd & Kniker stated that the species "differs from S. directa in its more elongate test and lack of a keel" but added that the two species "seem to be closely related and may prove indistinguishable". The holotype of S. brunswickensis (CC64279) is a megalosphaeric specimen 0.9 mm in length, 0.22 mm in width, that has 13 pairs of chambers in its biserial part. Paratype soecimens (CC64280) possess spiral portions that are generally narrower in diameter than the maximum width of the biserial part.


Text-fig. 104-4. Type specimens of four species from the Cushman Collection considered here to be junior synonyms of S. spectabilis (all camera lucida drawings by MAK, scale bar = 0.5 mm). 1-2. Spiroplectammina perplexa Israelsky, Lodo Formation, Tumey Hills, Fresno Co. CA. 1. Holotype (USNM 560501); 2. Paratype (USNM 560502). 3-4. Spiroplectammina brunswickensis Todd & Kniicker, middle Agua Fresca Formation, Brunswick Peninsula, Magallanes Province, Chile. 3. Holotype (CC 64279); 4. Paratype (CC 64280); 5-6. Spiroplectammina grzybowskii Frizzell, Mel Paso Shale, I.P. Co well 1755, 1960', paratypes (CC 39551, CC 33552); 7-9. Spiroplectammina mexiaensis Lalicker, Mexia Point Formation, "2 mi N & SW of the center of Mexia, Limestone Co., TX", 7. Holotype (CC 21924); 8-9. Paratypes (CC 21925; USNM 371544)


The generic affiliation of S. spectabilis is still unsettled due to the uncertain status of the genus Bolivinopsis. According to the current generic definitions of Loeblich & Tappan (1987), S. spectabilis clearly belongs in the genus Bolivinopsis. The type species of Spiroplectammina, (Textularia agglutinans var. biformis Parker & Jones, 1865), has organic cement, a rounded periphery, and an initial spiral part that is of lesser width than the biserial portion of the test. We have previously regarded the genus Bolivinopsis as nomen dubium following the suggestion of Frizzell (1943) because of the lack of preserved specimens of its type species, Bolivinopsis capitata Yakovlev, 1891. This species was reported from the Upper Cretaceous of Russia by Yakovlev, and the nature of its cement is unknown. Macfadyen (1933) considered B. capitata to be a junior synonym of Spiroplecta rosula Eherenberg, a species with an imperforate test and calcareous cement. Kisselman (1964) has pointed out that even in the type region of B. capitata, the designation "B. rosula" is used for these forms. Loeblich & Tappan (1987) remarked that "Cenozoic species previously assigned to Bolivinopsis are probably not congeneric", and listed the genus as restricted to the Late Cretaceous. They do not mention the composition of the cement, and Bolivinopsis is distinguished from Spiroplectammina in being more elongate and compressed, and in having a smoothly finished wall. Although we agree in principle with the generic scheme for the spiroplectamminids adopted by Loeblich & Tappan, in our opinion, the genus Bolivinopsis needs to be validated by examining the nature of its cement and designating a lectotype for its type species. Until this is done, we retain the Cenozoic forms in Spiroplectammina.

ILLUSTRATIONS: Plate 104 - Spiroplectammina spectabilis (Grzybowski) emend. Kaminski
Type specimens of S. spectabilis and Grzybowski's junior synonyms. Fig. 1a-c. "Spiroplecta spectabilis Grzybowski" (Grzybowski Collection; UJ-132-P 1/82a) Potok H-33, 170 m, probably the plesiotype of Grzybowski (1898, pl. 12, fig. 12). 1a,b- reflected light, 1c- cross-polarised light, Lectotype, Length = 1.0 mm; Fig. 2a,b. "Spiroplecta spectabilis Grzybowski" (Grzybowski Collection; UJ-132-P 1/82b), "Potok" exact locality unknown, 2a,b- reflected light, length = 1.15 mm; Fig. 3a-c. "Spiroplecta brevis Grzybowski" (Grzybowski Collection; UJ-132-P 1/83a) "Potok" exact locality unknown, plesiotype of Grzybowski (1898, pl. 12, fig. 13), 4a,b- reflected light, 4c- cross-polarised light, length = 0.72 mm; Fig. 4a,b. "Spiroplecta foliacea Grzybowski" (Grzybowski Collection; UJ-132-P 1/84a) Potok H-40, 24 m, 4a- reflected light, 4b- cross-polarised light, length = 0.74 mm; Fig. 5a-c. "Spiroplecta clotho Grzybowski" (UJ-133-P 2/100a) Bartne 14 (80), plesiotype of Grzybowski (1901, pl. 7, fig. 18), 5a,b- reflected light, 5c- cross-polarised light, length = 0.84 mm; Fig. 6a,b. "Spiroplecta costidorsata Grzybowski" (UJ-132-P 1/85b) Potok H-26, 96 m, probably the plesiotype of Grzybowski (1898, pl. 12, fig. 11), 3a- cross-polarised light, 3b- reflected light, L= 0.78 mm. All specimens from the Grzybowski Collection, courtesy of S. Geroch (light microscope photos).