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ASTEROTHECA GOLONDRINENSIS N. SP. FROM THE LOWER GOLONDRI JA SERIES OF THE BAJO DE LA LEONA, SANTA CRUZ, ARGENTINA

RAFAEL HERBST Facultad de Ciencias Exactas y Naturales y Agrimensura, University Nacional del Nordeste, Corrientes, Argentina

ABSTRACT

Asterotheca golondrinensis n. sp. is the new name proposed for fertile material of Pecopteris unita Bgt. from the Lower Permian Golondrina Series of Santa Cruz province, Patagonia, Argentina. European specimens known as Pecopteris unita Bgt. bear Ptychocarpus-type of sori and there is some confusion with specimens from other regions of the world. This makes it necessary to separate the Pata• gonian material bearing typical Asterotheca synangia.

RESUMEN

Sobre la base de material fracbficado se propone el nuevo nombre de A stero• theca golondrinensis n. sp. para los cjemplares de Pecoptel'is lInila Bgt. de la Serie La Golondrina, provincia Santa Cruz, Patagonia, Argentina. Los ejemplares europeos de Pecopteris unita Bgt. tienen fructificaciones del lipo Plychocarpus. mientras que existe confusion con respecto al material de otras regiones del mundo. Ello hace necesario segregar el material de Patagonia con tipicos sinangios de A sterotheca.

Specimens attributed to the widely dis• flora contained in the Lower Permian the abundant and diversified tributed Pecopteris unita Bgt. by these AMONGsediments of the Bajo de La Leona authors had not been found in fertile state (Santa Cruz province, Patagonia, Argentina) in the extensive collections at Tucuman described mainly by Archangelsky (1958) University (Instituto Miguel Lillo (LIL-PB)) and Archangelsky and de la Sota (1960) and La Plata Museum (LP-PB) either from there are only three pecopterids with simple the Bajo de La Leona or from the Permian lateral veins: Dizeugotheca waltoni, D. of Chubut province (Nueva Lubecka Series). neuburgiae and Pecopteris 16nita. Sterile The epithet P. 1mita has always been used specimens of these can usually be in Europe for specimens with fructifica• distinguished in general form, size, pinnule tions of the Ptychocarpus Weiss, 1869 type. arrangement and venation. In its use this genus has suffered a series Dizeugotheca is a genus erected by of modifications (or interpretations) by Archangelsky and de la Sota (1960) for Renault, Zeiller and others as shown by species with tetracapsulated fructifications Kidston (1925) for example where different (in groups of four, two upper ones piled types of sorijsynangia were included in it. over two lower ones) which differ neatly The species itself seems to have a wide from other Asterothecaceae. In the Bajo geographical and chronological distribution: de La Leona only the two above mentioned it was found in and Permian species are present but two more have later strata in Europe, China (Shansi), South been described from Permian sediments Africa (Rhodesia), New Guinea and finally of Patagonia and Bolivia respectively*. Patagonia; in some of these localities the * Incidentally. it seems that Maithy (1975) misinterpreted this genus as he includes in it the originally called Alethopteris and/or Pecopteris phegopteroides, for which he says (page 29): "Sori ... , arranged in a row along the margin of pinnules, laterally contiguous to one another, four sporangia in a sori, egg shaped, arranged in two rows opposite to each other". Later (page 36) he states: " Sori are present on vein endings composed of four freo sporangia arranged around a central point on the pinnule margin". These statements of the soral charactor's do not fit with the original definition of Dizeugotheca. 126 1-IERBST-AsTEROTHECA GOLONbRINJiNsls FROIlr LO\VER PERM1A1\ 127 name was applied to sterile material. It 1960 Pecopteris unita Archangelsky & de also seems to be rather polymorphous as la Sota: 105, figs. 38-41, lam V, it has been separated at least into two figs. 21, 23. varieties: var. typica and var. emarginata Diagnosis - Leaf at least tripinnate, main (see Kidston, 1925; Walton, 1929). Accord• rachis up to 12 mm wide, giving off the ing to Archangelsky (1958)in the Patagonian pinnae at angles of 70-80°; pinnae opposite material there exists a complete transition to alternate, linear, up to 110 mm long between these extremes called varieties. X 13 mm wide; pinnae rachis about 1 mm On the other hand, Pecopteris arc~~ata wide, sometimes striated. seems to be very close to P. lutita and Pinnules pecopterid, i.e. inserted by its has sometimes been confounded with it. whole base, with parallel lateral margins Lacey and Huard-Moine (1966) in their and rounded apex; pinnules at right angles discussion of Rhodesian specimens feel or slightly bent forward with respect to able to separate both species on morpho• the rachis, contiguous and free (or thinly logical grounds: P. arcuata is at least three basally united) in sterile specimens, some times bigger, bears proportionately more times free and separated (up to 2 mm) in lateral veins and the basal proximal lateral one fertile specimen. Size of biggest pin• vein of each pinnule constantly arises nules up to 7 x4 mm long/wide at base, directly from the pinna rachis instead of normally 5-6 x2-3 mm, and the smallest the pinnule mid-vein. They also discuss around 3.8-4 x2.5 mm long/wide at base. the possibility of this species being an Mid-vein distinct, straight, reaching the heterosporous fern (or even a Pterid.osperm) apex; lateral veins arising approximately because there are some "pteridospermic" at 45°, also straight, reaching th.e pinnule fructifications associated with it but there margin, subopposite to alternate, generally also are a few specimens bearing what look 3-4 pairs per pinnule. like true synangia. Six to eight almost circular tri- to Jongmans (1940) quotes, but does not tetrasporangiate synangia per pinnule, about describe, a Pecopteris unita from New 1.2 mm diameter, arranged in two slightly Guinea. According to this author the marginal rows. Sporangia pyriform (?), specimen of his fig. 8 undoubtedly bears fused to a common base, free in upper half, Ptychocarpus synangia but the photograph about 0.4-0.5 mm the longest axis, is not clear enough to confirm it; they which seems to lie parallel to the pinnule could also easily be considered of the surface. Asterotheca type. The sterile specimens Holotype - CTES-PB n° 11; Locality: sure~y look as typical Pecopteris unita Bajo de La Leona, Santa Cruz, Patagonia. speCImens. Horizon - Golondrina Series, Lower Per• This state of affairs makes of Pecopteris mran. (Ptychocarplts) unita Bgt. a very ample Cotype - CTES-PB nO2586; same locality species, it being probable that we are hand• and age. ling with more than one natural taxon. Additional M aterial- Many of the ~peci• In the Corrientes University collection mens quoted by Archange1sky and de la (CTES-PB) two specimens appeared with Sota (1960) have been reviewed and are typical Asterotheca synangia on Pecopteris defir itely included in the species. unita . It is felt therefore, that it becomes necessary to separate this "species" from the genus Pecopteris, and DISCUSSION to avoid undesired confusions with Pecopteris unita Bgt. to erect a new species, at least This new species is based only on two and .restricted for noW for the Patagonian fertile specimens, one of them being an speCImens. impression and counterimpression of an incomplete pinna (65 mm long) and the Asterotheca golondrinensis n.sp. other, two portions of segments, PI. 1, figs. 1-5; Text-fig. 13,-d with several incomplete pinnae attached. Additionally a rather great number of 1958 Pecopteris lmita Archangelsky: 39, sterile specimens in Tucuman, La Plata figs. 19-20. and Corrientes have been revised. tl-lE PAL..\EOBOTAKisT

b

;"- -" ( \ ----- \ '-_/ I ------==------=------..:::::::: ------= c

TEXT-FIG. 1 - a, b, sketches of specimen CTES nO 11 showing aspects of upper and lower surfaces respectively (approx. X 7). C, d, same for specimen CTES n° 2586 (approx. X 7).

In specimen CTES n° 11 the impression Specimen CTES nO 2586 is much smaller and counterpart show aspects of the upper in overall size, with pinnae about 8 mm and lower surface of the leaf respectively. wide and pinnules up to 4 x2.5 mm long/ On the former (PI. 1, figs. 1-3) six to eight wide at base. Synangia are of course more or less circular to oval bulges, 1.2 to 1.5 correspondingly smaller, about 0.6-0.7 mm diameter, located along the marginal mm diameter. As already mentioned, half of each hemilamina can be seen; they Archangelsky (1958) states that there is a are usually located between the lateral complete transitional series from smaller, veins, but in cases they appear as if "marginata" -type, to bigger, "typica" -type dissected by one of them and constituting of specimens. Apparently this remains true two different bodie8. But the lower surface for fertile specimens as well, as shown by clearly shows that it is a single body, an our two examples. almost circular tri- to tetrasr;orangiate syn• In general, the Golondrina Series did angium. In many of the synangia a central not render any palynomorphs up to date, short column can still be seen, which would and as expected no could be ob• indicate that the sporangia were fused tained here. at their bases; their upper half instead, The fertile specimens described in this in the same plane of the lamina, is paper are essentially coincident in all free. characters with the sterile ones described HERBST - ASTE1?OTHECA GOLONDRhJENSjS FRQ;\I LOWER PER;\liAK 129 as Pecopteris unita Bgt. by Archangelsky in that their pinnules are not contiguous (1958) and Archangelsky and de la Sota but separate, in some cases up to 2 mm, (1960) which is the reason to include them but this minimal distinction can easily in the newly created species. Only speci• be attributed to the natural polymorphism men CTES n° 11 shows a slight difference of this species.

REFERENCES

ARCHANGELSKY,S. (1958). Estudio geologico y LACEY, W. & HUARD-:\IODIE, D. (1966). Karroo paleontologico del Bajo de La Leona (Santa floras o( Rhodesia and l\lalawi. Part 2: The Cruz). Acta geol. lilloana, 2: 5-135. Glossopteris flora in the \Vankie District of ARCHANGELSKY.S. & DE LA SOTA, R. E. (1960). Southern Rhodesia. Symposittm on Floristics Contribuci6n al conocimiento de las Filices and Stratigraphy of Gondwanaland: Birbal Sahni permicas de la Patagonia extraandina. Acta Institute o( palaeobotany, Lucknow: 13-25. geo!. lilloana. 3: 85-126, lams I-VIII. l\lAITHY, P. K. (1975). Some contribution to the JONGMANS,\;Y. (1940). Beitrage zur kenntniss der knowledge of Indian Lower Gondwana . Karbon Flora Niederiandische New Guinea. Palaeobotan~st, 22 (1): 29-38. N!eded. Jaarsver. Geo!. Bttr. H eerlen,: 263-274. WALTON, J. (1929). The fossil flora of the Karroo KIDSTON, R. (1923-25). Fossil from the System in the Wankie District, Southern Carboniferous rocks of Great Britain. 111 em. Rhodesia. Bttll. geol. Stlrv. 5th. Rhod., 15: geol. Surv. G. Brit. (Paleont.), 2. 62-75.

EXPLANATION OF PLATE

PLATE 1 3. Same specimen; detail of lower surface with a few pinnules showing synangia. Approx. X 2.3. Asterotheca golondrineusis n. sp. 4. Same specimen; detail of upper surface showing the "bulges" representing synangia. Approx. X 2.3. 1, 2. Upper and lower surfaces of pinna of 5. Specimen CTES nO 2586; upper surface showing specimen CTES nO 11. Approx. X 1.3. venation and a few synangia. Approx. X 2·3. 130 THE PA1.AE0.130TANts-r

PLATE 1