Notes on Fossil Fruits

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Introduction

Fossil material of plants can be difficult to identify as to species, genus, or larger taxonomic unit, as usually what is found is individual parts of plants, such as wood, leaves, flowers, fruits or pollen, and these are often insufficient for identification, particularly for older material which is less closely related to modern material, and may be less well preserved. Consequently, and as fossils of one plant part often cannot be unambigiously associated with those of another plant part, palaeobotanists use form genera to classify parts of plants of uncertain taxonomic position. For fossil fruits the suffices -carpon, -carpum and -carpus are often used in generic names, indicating a similarity with the fruits of the modern genus whose name is combined with the suffix. It cannot be assumed that the fossil fruits represent a species particularly close to the modern genus; for example Craigia bronnii fruits were earlier interpreted as rutaceous or sapindaceous, and Nordenskioldia borealis and Sterculiocarpus coloradensis have been transferred to Trochodendraceae and Papaveraceae respectively.

I suspect that the genera and species of fossil malvaceous fruits listed below are far from an exhaustive coverage. Furthermore fossil fruits may be ascribed to a living genus, and this will be even harder to track down.

Banisteriaecarpum

Banisteriaecarpum giganteum (Goeppert) Kräusel is a fossil fruit consisting of a large samara. It was originally described as an Acer, and subsequently interpreted as malpighiaceous [a]. (Banisteria L. is a name that has been formally rejected in favoir of Heteropterys Kunth.) Recent opinion interprets it as sterculiaceous, and associates it with the leaf fossils Byttneriophyllum tiliaefolium. A second species has been described under the name Banisteriaecarpum papilio Andreanszky.

Byttneria

Byttneria (Buettneria) perplexans Cockerell,from the Florissant Formation of Colorado is represented by nutlets with persistent 5-lobed calyxes. It has also been identified as being verbenaceous, under the name of Petraea perplexans (Cockerell) MacGinitie, and more recently has been made the type of the fossil betulaceous genus Asterocarpinus [1], as Asterocarpinus perplexans (Cockerell) Manchester. Carpolithes macrophyllus Cockerell may represent the same or a related species.

Cantitilia

Cantitilia ("Kentish Lime") is a fossil genus known from seeds found in the Eocene London Clay strata of northern Kent (Isle of Sheppey and Herne Bay). On the basis of a detailed microstructural analysis Read and Chandler classify this genus as closely related to Tilia. Cantitilia differs from Tilia in having more (5) ovules in an ovary locule, and in the mature fruit being 2–3-seeded (most ovules not maturing), as opposed to the single-seeded state characteristic of Tilia.

The fruits of Cantitilia are syncarpous capsules. They are (4–)5-locular, many-ovulate, but with few maturing seeds, with axile placentation, and loculicidal dehiscence.

There are two known species (as of 1961), Cantitilia polysperma Reid and Chandler, and Cantitilia lobata Chandler. The fruits of the former are ovoid, 6½–13 mm long, 5–11½ mm wide, with seeds 4 to 5 mm long, 3 to 5½ mm wide. The fruits of the latter are deeply 5-lobed, 6 cm long by 11 mm across, with seeds about 4½ mm long and 3¾ mm broad.

Carpolithes

Carpolithes is a catchall for fossil fruits, and species will belong to different taxa.

Carpolithes bowerbanki Reid & Chandler is recorded from the Lower Eocene of England. A similar fruit is recorded from the Late Palaeocene Almont and Beicegel floras of North Dakota. These have been interpreted as malvalean, but have more recently been reinterpreted as ranunculaceous, as Paleoactaea bowerbanki ((Reid & Chandler) Pigg & DeVore and Paleoactea nagelii Pigg & DeVore [2].

Christianacarpum

Christianacarpum is a form genus representing fossil fruits similar to those of the living genus Christiana,

Christianacarpum quinquelocularis, from the Eocene of France, is interpreted as belonging to a plant which belongs to the genus Christiana.

Daberocarpon

Daberocarpon is a presumed malvaceous fruit. Daberocarpon gerhardii Chitaley & Sheikh is based on a 10-locular fruit from the uppermost Cretaceous of the Deccan Intratrappean Beds of India [b]. Each locule is single-seeded.

The authors suggested an affinity with tribe Malveae. However the fruit preceeds the appearance of malvoid pollen within the pollen record, which suggests that we should look elsewhere for the true affinities.

Etheridgea

Etheridgea subglobosa is a fossil fruit from the Late Cretaceous of Australia, which is assigned to Tiliaceae (Grewioideae? Brownlowiodeae?).

Firmiana

Fruits ascribed to the fossil species Firmiana yunnanensis are reported from the Miocene of Yunnan [c].

Fracastoria

Fracastoria is a fruit fossil. It was described, and placed in Sterculiaceae, in the mid 19th century by Massalongo [d] , from specimens of large fruits from Bolca in northern Italy. Massalongo appears to have been a splitter, and I am skeptical that there are as many distinct taxa as he described. Most subsequent opinion treats Fracastoria as the fruits of a palm (e.g. [e]), though it has been treated as related to the much smaller Hightea (see below).

The described species are :-

Hightea

Hightea is a fruit fossil, assigned to Malvaceae, from the Eocene of Britain. Bowerbank [3] described 10 species - Hightea attenuata, Hightea elliptica, Hightea elegans, Hightea fusiformis, Hightea inflata, Hightea minima, Hightea orbicularis, Hightea oviformis, Hightea turbinata and Hightea turgida.

Luehea

Fruits assigned to Luehea newberryana (Knowlton) MacGinitie are found in the Early and Middle Eocene of Wyoming. These are now considered to belong to Populus cinnamonoides [4].

Malvacarpus

Malvacarpus is a form genus representing fossil fruits similar to those of extant mallows.

The type is Malvacarpus tertiarius Berry, from the Miocene of Argentina. The species Malvacarpus guinazui Berry is recorded from the Palaeocene or Eocene of the Rio Negro region of Argentina. The name Malvacarpus octoloculus has also been used.

Nordenskioldia

Nordenskioldia is a fruit fossil once assigned to Tiliaceae, but now considered as a member of Trochodedraceae, with an extensive fossil record in time (Palaeocene to Miocene) and space (North America, Greenland, Scotland, Spitzbergen, Russia, Inner Mongolia). The leaf genus Zizyphiodes is thought to represent the same plant.

Pentaloculocarpon

Pentaloculocarpon chitaleii Kapgate & Kapgate is a fruit fossil from the Intertrappean beds of the Deccan, which may be malvaceous. It is a pentalocular loculicidal capsule with axile placentation and single-seeded locules, of ovoid shape measuring 850µ by 1mm. The pericarp is differentiated into a outer thin epidermal zone, followed by middle multilayered parenchymatous zone consisting intercellular spaces and mucilage canals, followed by 1-2 layered compact inner zone. The seed has a membranous coat. The embryo is dicotyledonous and embedded in endosperm tissue. [f]

(This may not be validly published, as I have found no evidence of publication beyond a conference poster.).

Pteleaecarpum

Pteleaecarpum is a form genus representing fossil fruit mistakenly interpreted as related to those of Ptelea (Rutaceae). However Pteleaecarpum bronnii is now recognised as being the fruit of a species of Craigia (Tilieae), of which floral and foliar material is also available [g]. Pteleaecarpum europeum represents the same species [5]. Fossil material of Craigia bronnii is known from several localities in Europe, including the Lower Oligocene of Hungary, the Lower Miocene of Bohemia, and the Upper Miocene of Germany

Pterospermites

Reevesia

Reevesia humikii

Sphinxia

Sphinxia ovalis is a fossil fruit from the Londay Clay interpreted as being Dombeyoid, and most closely allied to Dombeya and Trochetia. (The name Sphinxia is also applied to a Devonian lycopsid; one or other usage of this generic name will be invalid.)

Sterculia

Fruit assigned to Sterculia palaeovillosa on the grounds of its siimilarity to the living Sterculia villosa is recorded from the Oligocene of Assam [6].

Sterculiocarpus

Sterculiocarpus is a form genus representing fossil fruits similar to those of living Sterculia.

The species Sterculiocarpus coloradensis Berry has been reduced to synonyny with Palaeoaster porosa (Papaveraceae) [7]. Leaf material named Sterculia coloradensis consists of deeply three lobed leaves that don't present a papaveraceous aspect, and presumably does not represent the same taxon.

Other names which has been published are Sterculiocarpus eocenicus Berry and Sterculiocarpus sphericus Berry, from the Eocene Wilcox Fm, and Sterculiocarpus sezannelloides Berry from the Eocene Lagrange Fm. I do not know whether these represent genuine sterculioid fruits.

Sterculiocarpus etayoi is South American.

References

  1. Manchester, S.R, & Crane, Peter R., A New Genus of Betulaceae from the Oligocene of Western North America, Bot. Gaz. 148(2): 263-273 (1987)
  2. Pigg, Kathleen B. & DeVore, Melanie L., Paleoactaea gen. nov. (Ranunculaceae) fruits from the Paleogene of North Dakota and the London Clay, Am. J. Bot. 92(10): 1650-1659 (2005)
  3. Bowerbank, James Scott, A history of the fossil fruits and seeds of the London clay (1840)
  4. Manchester, S.R. et al, Foliage and Fruits of Early Poplars (Salicaceae: Populus) from the Eocene of Utah, Colorado, and Wyoming, International Journal of Plant Sciences 167: 897-908 (2006)
  5. Kvaček, Z., Early Miocene records of Craigia (Malvaceae s.l.) in the Most Basin, North Bohemia - whole plant approach, Journal of the Czech Geological Society 49(3/4): 161-171 (2004)
  6. Mehrota, Two new fossil fruits from Oligocene sediments of Makum Coalfield, Assam, India, Current Science 79(10): 1482-1483 (2000)
  7. Smith, Una R., Revision of the Cretaceous Fossil Genus Palaeoaster (Papaveraceae) and Clarification of Pertinent Species of Eriocaulon, Palaeoaster, and Sterculiocarpus, Novon 11(2): 258-260 (2011)

Bibliography

  1. Kr�usel, R., Die terti�re �Riesenahorn� Banisteriaecarpum nov. gen. Die systematische Stellung von Acer giganteum und Acer otopteris Goepp., Abh. Seckenberg. Naturforsch. Ges. 485: 75-80 (1952)
  2. Chitaley, S.D. & Sheikh, M.T., A ten locular petrified fruit from the Deccan Intertrappean Series of India, The Palaeobotanist 20(3): 297-299 (1973)
  3. Sanping Xie, Steven R.Manchester, Kenan Liu, Yunfeng Wang & Yang Shao, Firmiana (Malvaceae: Sterculioideae) fruits from the Upper Miocene of Yunnan, Southwest China, Geobios 47(4): 271-279 (2014)
  4. Massalongo, D.A.B, Palaeophyta rariora formationis tertiariae Agri Veneti,, Acta Caes. R. Inst. Ven. 3(3): 35-38 (1858)
  5. Tralau, H., The genus Nypa van Wurmb, Kungliga Svenska Vetenskapsakademiens Handlingar 10: 5-29 (1964)
  6. Kapgate, V.D. & Kapgate, D.K.., A pentalocular fruit from the Deccan Intertrappen beds of India, poster at XVI International Botanical Congess
  7. Buzek, Cestmir, Kvaček, Zlatko & Manchester, Steven R., Sapindaceous Affinities of the Pteleaecarpum Fruits from the Tertiary of Eurasia and North America, Bot. Gaz. 150(4): 477-489 (1989)

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