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Mollusk Fauna of the Pacaya Samiria Reserve
Cristián F. Ituarte
Division of Invertebrate Zoology, Museo de La Plata, 1900 La Plata, Buenos Aires, Argentina
List of taxa (16 spp.):
CLASS: BIVALVIA
Cataloged lots: BIVALVES.PDF
Super-Order. UNIONOIDA
Family Mycetopodidae
Genus Anodontites
A. elongatus (Swainson, 1823)
Fig. 1.
A. trapesialis (Lamarck, 1819)
Fig. 2.
Genus Mycetopoda
M. siliquosa (Spix, 1827)
Fig. 3.
Family Hyriidae
Genus Castalia
A. ambigua Lamarck, 1819
Fig. 4.
Super-Order VENEROIDA
Family Sphaeriidae
Genus Eupera
E. simoni (Jousseaume, 1889)
Fig. 5.
Genus Pisidium
P. sterkianum Pilsbry, 1897
Fig. 6.
P. iquito Ituarte, 2004
Fig. 7
Family Corbiculidae
Genus Corbicula
C. fluminea (M ü ller, 1774) (introduced from Asia )
CLASS GASTROPODA
Cataloged lots: GASTROPODS.PDF
Order PULMONATA
Suborder: BASOMMATOPHORA
Family Ancylidae
Genus Gundlachia Pfeiffer, 1849
G. aff. radiata (Guilding, 1828)
Fig. 8.
Family Lymnaeidae
Genus Lymnaea Lamarck, 1801
Lymnaea sp. indet.
Family Physidae
Genus Stenophysa von Martens, 1898
Stenophysa sp. indet.
Family Planorbidae
Genus Biomphalaria Preston, 1910
B. cf. tenagophila d' Orbigny, 1835
Fig. 9.
Genus Drepanotrema Fischer & Crosse, 1880
D. depressissimum (Moricand, 1839)
D. pileatum Paraense, 1971
Fig. 10.
Suborder STYLOMMATOPHORA
Family Succinaeidae
Genus Omalonix d' Orbigny, 1841
O. unguis (d' Orbigny, 1835)
Fig. 11.
Order CAENOGASTROPODA
Family Ampullariidae
Genus Pomacea Perry, 1811
P. maculata (Perry, 1810)
Fig. 12-13.
Photographs:
Fig. 1. Anodontites elonga tus. Outer view of a right valve (upper) and inner view of a left valve (below).
Fig. 2. Anodontites trapesial is . Outer view of a right valve.
Fig. 3. Mycetopoda siliquo sa. Outer view of a left valve.
Fig. 4. Castalia ambigua
Fig. 5. Eupera simoni. Outer view of a right valve
Fig. 6. Pisidium sterkianum. Right lateral (at left) and posterior (at right) views of a specimen from a small stream that flows into the Pacaya River .
Fig. 7. Pisidium iquito Right lateral (at left) and posterior (at right) views of a specimen from Cocha Tamara
Fig. 8. Gundlachia aff. radiata (Guilding, 1828)
Fig. 9. Biomphalaria teganophila
Fig. 10. Drepanotrema cf. pileatum
Fig. 11. Omalonix unguis . A dorsal view of a specimen collected from floating meadows at Pacaya River .
Fig. 12. Pomacea maculata
Fig. 13. Pomacea maculata
Abstract of research findings: Progress made in the taxonomic identification of mollusks collected during the 2002 low water period in the Pacaya - Samiria Reserve, Peru, represents an increase in the, still weak and fractionary, knowledge of the Peruvian freshwater fauna. The freshwater molluscan assemblages in the surveyed area is composed of 10 gastropod and 7 bivalve species. From a quantitative point of view, this diversity levels are in agreement with the diversity of genera reported in the most recent faunistic account of Peruvian Amazon freshwater mollusks (Ramírez, 2003). However, concerning the composition of molluscan assemblages, our survey resulted in the addition of 2 gastropod and 2 bivalve genera (5 species, one new to science) not previously reported for the Amazonian region, and one gastropod species of Ancylidae not previously reported for the area. Among Bivalves, three genera of Unionoida, large bivalves living in muddy substrates, were identified: the mycetopodids Anodontites and Mycetopoda , and the hyriid Castalia . The genus Anodontites was represented by 2 species: A. trapesialis (Lamarck, 1819), and A. elongatus (Swainson, 1823) and Mycetopoda by only one species, Mycetopoda siliquosa (Spix, 1827). Castalia ambigua Lamarck, 1819 was the sole Hyriidae collected. In close association with floating vegetation, the family Sphaeriidae (Bivalvia) was represented by Eupera simoni (Jousseaume, 1889), a species mainly living on roots of Potamogeton , a very common component of floating meadows at Pacaya - Samiria Reserve. Pisidium , another sphaeriid genus, was only found living on soft bottoms with a high content of vegetable debris in non-running water corps (the so-called "cochas") and on muddy bottoms in small streams. Pisidium sterkianum Pilsbry, 1897, showed to be one of the more widely distributed South American Pisidium species, ranging exclusively in water bodies of the eastern (Atlantic) drainage) from Venezuela to Buenos Aires Province in Argentina, covering approx. 50º Latitude degrees. Among Gastropoda, the Succinaeidae Omalonix unguis (d´Orbigny1835) as well as the family Lymnaeidae (a still unidentified genus) were not previously reported from Peruvian Amazonia (Ramírez, 2003). The remaining sampled gastropods, the Planorbidae Biomphalaria and Drepanotrema , as well as the Ampullariidae Pomacea were genera largely known as very common in Amazonian environments.
Phylogeny and Biogeography (By James Albert ): Among Neotropical freshwater mollusks there are at least seven bivalve NFCs and nine gastropod NFCs (Appendix). Bivalves are more diverse at lower taxonomic levels and less diverse at higher levels than are gastropods; whereas bivalves constitute 44% of the Neotropical freshwater mollusk clades, they constitute 64% of the species. All but 1 of these 16 mollusk NFCs trace their origins to the Cretaceous (or earlier); only the pachydontine corbulids have an origin in Neotropical freshwaters from a Tertiary Marine invasion.
Within the Unionoida (large pearly mussels; Haas, 1969a, 1969b; Graf, 2000, 2001) there are at least three Neotropical freshwater clades. The Unionoidea (forming Glochidia) includes one Neotropical clade, the Hyriinae , with 10 genera and 55 species. The sister taxon to Hyriinae is the Australian Hyridellinae (8 genera, 27 species). Fossil Hyriinae date from the Tacuarembó Formation (northern Uruguay ) with a poorly-defined age between late Triassic and early Cretaceous (Martinez & Figueras, 1993). The Etherioidea (=Muteloidea) (forming Lasidia) includes two Neotropical clades: Etheriidae (3 genera, 4 species) and Mycetopodidae (10 genera, 40 species)with oldest fossils: in the Tertiary. The Etherioidea also includes the African Iridinidae (6 genera, 22 species).
Unlike many taxa represented in the Neotropics, the Unionoida is not most diverse in this region. The family Unionidae has 120 genera (76% of the total number in the order); the Hyriidae: 18 gen. (11%); the Mycetopodidae: 10 gen. (6%); the Iridinidae: 6 gen. (4%); the Etheriidae: 3 gen. (2%) and the Margaritiferidae: 2 gen. (1%) (Graf, 2001). The Nearctic Region with 65 gen. represents the 39% of the total for the order Unionida (159); the Oriental Region: 46 gen. (28%); the Neotropical Region: 21 gen. (13%); the Ethiopian Region: 16 gen. (10%); the Palearctic Region 8 gen. (5%); the Australasian 9 gen. (5%).
Some new evidence concerning phylogeny of Unionida (Graf, 2000) contradicts the largely accepted phylogenetic scheme proposed by Parodiz and Bonetto (1963) based exclusively on larval types. When Graf (2000) included in his phylogenetic analysis characters from both, larval and adult stages resulted that the Unionoidea is not monophyletic, and that the Hyriidae is part of a natural taxon when included among the Etherioidea. Despite the fact that they have glochidium, the Hyriidae share a more recent common ancestor with the Etherioidea than with any Unionoidea. The Etherioidea (Hyriidae, (Iridinidae, Etheriidae) is diagnosed by three adult anatomical synapomorphies. The lasidium larvae is hypothesized to be derived from glochidia (a fact not easily accepted by many). Finally, the analysis by Graf does not found support for a monophyletic Mycetopodidae.
Four additional Neotropical freshwater bivalve clades are: the corbiculid Neocorbicula (2 spp., and four clades of Neotropical sphaeriids: Eupera (15 spp.), Pisidium (22 spp.) , and Sphaerium+Musculium (5 spp.). Corbiculids are known from the Bolivian and Patagonian Paleocene (Parodiz, 1965, 1969). Neotropical sphaeriids (small pill and finger-nail clams) are represented by four genera: Eupera , Pisidium , Sphaerium and Musculium ). Eupera includes at least 30 nominal Neotropical species ( Dreher Mansur, 1993); only 6 species are known from Africa and Madagascar (Daget, 1998). Among Sphaeriids, only the genus Eupera is presently distributed exclusively in the African and Neotropical Regions, with a northern extension in coastal areas of the United States from Texas to North Carolina . Eupera dates from the French Paleocene (Thannetian). Eupera is in need of revision and the actual species diversity is probably about 15 species. There are a number of undescribed Eupera species in Africa . The maximum size for an Eupera species is 10 mm in shell length (usually 5-7 mm). The genus Pisidium has a world-distribution since at least the Cretaceous. Pisidium includes 22 nominal species from South America (Pilsbry, 1897, 1911; Ituarte 1996, 1999, 2000, 2001; and references therein). Data from Central America and Southern Mexico are strongly dubious. Of the 22 nominal species of Pisidium , 3 are dubious species and 4 need revision to state their validness. 24 species of Pisidium are known from Africa (Daget, 1998). Maximum shell length for a South American Pisidium species is about 7.5 mm. The remaining Sphaeriidae comprise the two poorly defined genera Musculium and Sphaerium (5 spp.) of uncertain phylogenetic affinity.
The colonization of freshwater habitats from marine environments is a phenomenon closely related with the evolution of brooding (Graf and O'Foighil, 2000). All freshwater Unionoida developed some kind of brood protection as a way to overcome the disadvantage of having an extremely fragile free planktonic larvae in highly unstable environments. As a result, sphaeriids and corbiculids abandoned the planktonic larval stage changing to a direct mode of development of offspring, which are brooded within the demibranchs; as a consequence, their dispersal capacity is significantly reduced. Among the Unionoida, a relatively short brooding period within branchial pouches is followed by a peculiar larval stage (either glochidium or lasidium according to the taxa) parasite on fishes, which represent an alternative way of dispersal (only a few Unionids have secondarily recovered the direct development without parasitic phase) (Parodiz and Bonetto, 1963; Graf and O'Foighil, 2000). Interestingly, species forming glochidia are cosmopolitan(including Unionidae and Margaritiferidae in the Holarctic and Hyriinae in South America ); whereas those forming lasidia (i.e., Mycetopodidae) are restricted to South America and Africa (Wächtler et al. 2001).
The phylogeny and biogeography of Neotropical freshwater gastropods is poorly known. The Neotropical freshwater gastropod fauna is represented by at least nine family-level taxa with cosmopolitan or Gondwanan distributions (e.g., Ampullariidae , Ancylidae, Chilinidae , Hydrobiidae, Lymnaeidae, Physidae , Planorbidae, Succinidae, Thiaridae). Each of these families represents a minimum of one NFC. At least six gastropod clades endemic to Neotropical freshwaters have their nearest relative in African freshwaters, suggesting a Gondwanan origin of at least 100 Ma. These taxa are: Neotropical ampullariids (20 spp.), cochliophine hydrobiids (12 spp.), Neotropical chilinids , (diversity unknown), Neotropical ancylids (30 spp.), the thiarid Aylacostoma + Hemisinus (10 spp.), and the planorbid Biomphalaria (6 spp.). Three additional Neotropical freshwater gastropod clades are Physidae (1 spp.), Succinidae (3 spp.), and Lymnaeidae (3 spp.).
Additional information on the phylogenetic age of Neotropical freshwater gastropods is available from fossils and other phylogenetic and biogeographic data. Biomphalaria is known from fossils dating to the Paleocene of South America (c. 50 Ma.; Parodiz, 1969). The thiarid clade Aylacostoma + Hemisinus exhibits as cis-trans Andean distribution (with representatives in Central America ) suggesting a minimum age of c. 12 Ma. (Albert et al., in rev.). The 12 genera of extant cochliophine hydrobiids in the Amazon are relics of aMiocene radiation that included 75 spp. in 15 genera (Wesselingh et al., 2002). Extant cochliophine snails are epifuanal semi-infaunal dwelling detritivores and grazers that occur in strictly freshwater or brackish water habitats. Of the two molluscan clades that underwent explosive radiation in Miocene Lake Pebas, the cochliophines were derived from a lineage tracing its origin to freshwaters in the Cretaceous, whereas the pachydontines (corbulid bivalves) were derived from a marine lineage. Most strictly freshwater mollusks are salt-intolerant and feed exclusively on freshwater aquatic vegetation (Wesselingh et al., 2002).
References
Daget, J. 1998. Catalogue raisonné des Mollusques bivalves d´eau douce africains. Leiden/Paris, Backhuys Publishers/Orstom.
Dreher Mansur, M. C. 1993. Morphologische Untersuchungen an Eupera Bourguignat, 1854, und Byssanodonta Orbigny, 1846. Zur phylogenetischen Systematik der Sphaeriidae und Corbiculidae (Bivalvia: Veneroida). Tübingen, Universität Tübingen: 125.
Graf, D. L. 2000. The Etheroidea revisited: a phylogenetic analysis of Hyriid relationships (Mollusca: Bivalvia: Paleoheterodonta: Unionoida). Occasional papers of the Museum of Zoology , Michigan 729: 1-21.
Graf, D. L. 2001. A Phylogenetic Perspective on the Evolution of the Unionoida (Mollusca Bivalvia Palaeoheterodonta): Using Pattern to Test Hypotheses of Macroevolutionary Process. Ph.D. Dissertation, University of Michigan , Ann Arbor , Michigan .
Graf, D. L. and D. O'Foighil. 2000. The evolution of brooding characters among the freshwater pearly mussels (Bivalvia: Unionoidea) of North America . Journal of Molluscan Studies 66: 157-170.
Haas, F. 1969a. Superfamilia Unionacea . [In] R. Martens and W. Hennig (eds.). Das Tierrich , Lieferung 88, 663 pp. Walter de Gruyter and Co., Berlin.
Haas, F. 1969b. Superfamily Unionacea. pp. N411-N470. [In] R.C. Moore (ed.). Treatise on Invertebrate Paleontology, Part N, Mollusca, 6. Volume 1: Bivalvia. Geological Society of America and University of Kansas Press, Lawrence, Kansas.
Ituarte, C. F. 1996. Argentine species of Pisidium Pfeiffer, 1821, and Musculium Link, 1807 (Bivalvia: Sphaeriidae). The Veliger 39(3): 189-203.
Ituarte, C. F. 1999. Pisidium chilense (d´Orbigny, 1846) and new species of Pisidium C. Pfeiffer, 1821 from southern Chile (Bivalvia, Sphaeriidae). Zoosystema 21(2): 249-257.
Ituarte, C. F. 2000. Pisidium taraguyense and Pisidium pipoense , new species from northeastern Argentina (Bivalvia: Sphaeriidae). The Veliger 43(1).
Ituarte, C. F. 2001. Pisidium chiquitanum new species from Santa Cruz de la Sierra, Bolivia (Bivalvia: Sphaeriidae). The Nautilus 115(2): 50-54 .
Ituarte, C.F. 2004. Sphaeriidae (Bivalvia) from Peruvian Amazon floodplains, with the description of Pisidium iquito, new species. The Nautilus 118 (4): 167-174.
Martínez, S. and A. Figueiras. 1991. Two new species of Mesozoic Diplodon (Bivalvia: Hyriidae) from Uruguay. Walkerana 5: 217-223.
Martínez, S. and A. Figueiras. 1993. A new Unionoidea (Mollusca, Bivalvia) from the Tacuarembó formation (Upper Triassic-Upper Jurassic), Uruguay. Journal of Paleontology 67(6): 962-965.
Parodiz, J. J. 1969. The Tertiary non -marine Mollusca of South America. Annals of the Carnegie Museum 40: 1-242.
Parodiz, J. J. 1969. The Tertiary non marine Mollusca of South America. Annals of the Carnegie Museum 40: 242 pp.
Parodiz, J. J. and A. A. Bonetto. 1963. Taxonomy and zoogeographic relationships of the South American Naiades (Pelecypoda: Unionacea and Mutelacea). Malacologia 1 179-214.
Parodiz, J. J. and L. Hennings. 1965. The Neocorbicula (Mollusca Pelecypoda) of the Paraná - Uruguay basin, South America. Annals of the Carnegie Museum 38(3): 69-96.
Pilsbry, H. A. 1897. New species of mollusks from Uruguay. Proceedings of the Academy of Natural Sciences of Philadelphia(May, 1897): 290-298, 2 pla.
Pilsbry, H. A. 1911. Non-marine Mollusca of Patagonia. Reports of the Princeton University Expedition to Patagonia, 1896-1899. Vol 3(Part 5): 513-633.
Ramírez, R. 2003.Moluscos del Perú. in: Malacología Latinoamericana, Z. Barrientos & J. Monge-Nájera, eds. International Journal of Tropical Biology and Conservation Vol. 51 (Suppl. 3): 225-284.
Wesselingh, F.P. M.E. Räsänen, G. Irion, H.B. Vonhof, R. Kaandorp, W. Renema, L. Romero Pittman, and M. Gingras. 2002. Lake Pebas : a palaeoenvironmental reconstruction of a Miocene, long-lived lake complex in western Amazonia . Cainozoic Research 1(1-2):35-81.
Wächtler, K., M. C. Dreher-Mansur and T. Richter. 2001. Larval types and early postlarval biology in Naiads (Unionoida). In: Ecological Studies, Vol. 145, G. Bauer and K. Wächtler (eds.) Ecology and evolution of the freshwater mussels Unionoida; pp.93-125. Springer-Verlag , Berlin , Heidelberg .
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