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Philadelphia, PA, United States

The Academy of Natural science of Drexel University, formerly the Academy of Natural science of Philadelphia, is the oldest natural science research institution and museum in the New World. It was founded in 1812 by many of the leading naturalists of the young republic with an expressed mission of "the encouragement and cultivation of the science". For over two centuries of continuous operations, the Academy has sponsored expeditions, conducted original environmental and systematics research, and amassed natural history collections containing more than 17 million specimens. The Academy also has a long tradition of public exhibits and educational programs for both schools and the general public. Wikipedia.


Potapova M.,Academy of Natural Sciences of Philadelphia
Proceedings of the Academy of Natural Sciences of Philadelphia | Year: 2013

The goal of this study was to investigate type materials of 22 Navicula species described by Ruth Patrick in 1959. Type specimens of two species could not be found on the holotype slides. The holotypes of 20 other taxa were located and imaged. Specimens of 11 taxa from type materials or from the type localities were investigated with electron microscopy and the details of their ultrastructure were described. On the basis of this examination, six Navicula species were transferred to other genera. The following new combinations were made: Hippodonta dulcis Potapova nom. nov., H. gravistriata (Patrick) Potapova comb, nov., Fallacia latelolongitudinalis (Patrick) Potapova comb, nov., F. duomedia (Patrick) Potapova comb, nov., Selllaphora subfasciata Potapova nom. nov., and S. secura (Patrick) Potapova comb. nov. Based on the available data, nine species described by Patrick were found to be taxonomic synonyms of taxa described earlier by other authors. Future studies of more abundant populations of Patrick's species and type materials of the taxa assumed to be synonymous, may, however, reveal differences between them and prove some of Patrick's taxa to be separate species. Source


The nuclear gene phytochrome A (PHYA) from 71 species of crown clade Apocynaceae (subfamilies Asclepiadoideae, Secamonoideae, Periplocoideae, and four lineages of Apocynoideae) and outgroups is used to (1) test the chloroplast phylogeny that places the African tribe Baisseeae, with solitary pollen grains, as sister to the pollinia-bearing milkweeds (Secamonoideae plus Asclepiadoideae); (2) resolve the position of tetrad-bearing Periplocoideae, the proposed milkweed sister group based on morphology; (3) place the enigmatic Dewevrella; and (4) clarify relationships of the three other primary crown clade lineages: Rhabdadenia, New World clade, and Asian clade. Separate analyses of PHYA and chloroplast sequences agree in placing an African monad-bearing clade (Baisseeae plus Dewevrella) as the sister group of the milkweeds. Combined PHYA and chloroplast datasets under parsimony and maximum likelihood reject Periplocoideae as the milkweed sister group with statistical significance. Rhabdadenia is placed as sister to the rest of the crown clade, consistent with aspects of its floral morphology and wood anatomy, but without statistical support. Other relationships among the primary crown clade Apocynaceae lineages are also not supported statistically, but power analysis indicates that four to eight times as many characters (26,376-52,752 aligned positions) will be sufficient for a robust estimate. Source


Robertson R.,Academy of Natural Sciences of Philadelphia
American Malacological Bulletin | Year: 2012

C-type protoconchs have been thought always to reflect a "direct" or short pelagic development, an idea deriving from Thorson's (1946) study of the early development (besides planktonic veligers) of only one pyramidellid species. The small-shelled genus Fargoa Bartsch (1955), some ectoparasitic on serpulid polychaetes such as Hydroides, apparently uniformly has C-type protoconchs. The eggs and early larval development of Fargoa dianthophila (Wells and Wells, 1961) (shells < 1.8 mm) and F. bartschi (Winkley, 1909) (< 4.0 mm) were studied in the laboratory at Woods Hole, Massachusetts. The eggs were only 53 to 57 μm and 55 to 60 μm in diameter, respectively, and as would be expected from eggs this size both species are definitely planktotrophic. Few other pyramidellids or other "opisthobranchs" lay eggs this small, and the single Brachystomia (Monterosato, 1884) species studied by Thorson (1946) was also planktotrophic. The protoconch diameters of F. dianthophila and F. bartschi are, respectively, about 260 to 315 μm and about 210 to 230 μm, i.e., surprisingly large. This variation parallels neither the nearly uniform egg size nor the disparate adult shell sizes. No attempt was made to rear the larvae in the laboratory because there were only a few newly hatched veligers and these protoconchs indicated much growth in the plankton. These Fargoa veligers may remain planktonic for longer times than planktotrophic Boonea Robertson (1978). One protoconch, an egg capsule containing a late blastula, and a newly hatched swimming veliger are illustrated. Small pyramidellids appear to lay the smallest eggs, but this seems not to be true of other "opisthobranchs.". Source


Robertson R.,Academy of Natural Sciences of Philadelphia
American Malacological Bulletin | Year: 2012

Major papers on pyramidellid protoconchs, larval development, and larval ecology are reviewed, partly with illustrations. Larval shell coiling (including hyperstrophy and heterostrophy) is discussed. A-, B-, and C-type protoconchs are figured and distinguished. Those of species in the Baltic and northwestern France have been used to infer modes of larval development. The reliability of many of these inferences is questioned. Egg, embryo, and veliger morphologies, functions and terminologies are then discussed, including confusions of the terms "egg" and "capsule." The pigmented mantle organ or gland ("PMO") is briefly reviewed. Previously published data on the eggs and larvae of Brachystomia "scalaris" (Macgillivray, 1843), of"Turbonilla" cummingi Hori and Okutani, 1997, and of "Odostomia columbiana Dall and Bartsch, 1907", are reviewed in detail with some new interpretations. In the first of these species, egg size variation is possibly salinity-induced and may cause variation in mode of development. Alternatively, different species may be involved. In the second named species, lecithotrophy straddles intracapsular metamorphosis sympatrically. In the third species, some of its unusual features may have been induced by low temperatures. "Mid-water metamorphosis" is then discussed. It is concluded that species with A-type protoconchs may be constrained to planktotrophy. Source


Marina P.,Academy of Natural Sciences of Philadelphia
Diatom Research | Year: 2011

Several species oí Nupela were found in samples collected in 2009 from streams and aerophytic habitats of North-central Pennsylvania. Some of these species appeared either new to science or insufficiently known and, although described earlier, not yet transferred to the genus Nupela. This triggered an investigation of type materials of several Nupela species described in the past, especially those with type localities in the Appalachian region. As a result of this study, two new Nupela species, N. elegantula and N.frezelii are described, while Navicula pennsylvanica, Navicula poconoensis and Achnanthes subrostrata are transferred to Nupela. Examination of type material of Achnanthes subrostrata var. appalachiana showed that this taxon is conspecific with Nupela lapidosa. © 2011 The International Society for Diatom Research. Source

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