Anatomical description of Pisidium johnsoni EA Smith, 1882 (Bivalvia : Sphaeriidae) from Madagascar

3 Pages·2002·2.4 MB·English

by  A V Korniushin

THE VELIGER
© CMS. Inc., 2002
The Veliger45(4):356-360 (October 1, 2002)
NOTES, INFORMATION & NEWS
The Century's Finest ence of stasis in the fossil record had been noticed much
David R. Lindberg earlier (e.g., Dall, 1877), but rather than eschew it as ar-
tifact (or use it to argue against Darwinian evolution).
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At the beginning of the last century the malacological macroevolution theory.
world was privileged to have an array of distinguished In 1977 Ontogeny and Phylogeny was published. This
practitioners. William H. Dall and Paul Bartsch at the seminal volume recovered the baby that had been thrown
SmithsonianInstitution, Henry A. Pilsbry attheAcademy out with Haeckel's bathwater, and foreshadowed the re-
of Natural Sciences in Philadelphia, Harold Heath at surgence ofthe field ofevolutionary development. It also
Stanford University. S. Stillman Berry in Redlands, Cal- had a profound influence on a cohort ofgraduate students
ifornia, and numerous others led the way in describing who read the book in seminars across the country. Mol-
the living and fossil molluscan fauna of North America. luscan examples were scattered throughout the text, in-
These workers ultimately described over 10,000 taxa, and cluding Ockelman's (1964) study of small insular bi-
their efforts capped what might be thought of as the valves, Stanley's (1972) progenetic transitions in bivalve
"Golden Age" of American malacology. However, the habits. Hoagland's (1975) dissertation work on life his-
most influential malacologist of the twentieth century tory evolution in Crepidula, as well as Steve's own work
would not be bom for another 40 years. In contrast, he on Poecilozonites and Cerion.
would describe only a handful of taxa in a career that It is not surprising that mollusks also figured promi-
spanned the last half of the century, but there is no de- nently as study organisms among Steve's students. These
nying the import of his contributions to the field of mal- students included Warren Allmon (1988) who investigat-
acology and far beyond. ed heterochrony in the evolution of Turritella shell mor-
Stephen Jay Gould was born on September 10, 1941, phology, Dana Geary (1986) who studied aLate Miocene
in Queens, New York. Like many students ofnatural his- radiation ofmelanopsid gastropods, and Jane Rose (1990)
tory his fascination with organisms began at an early age, who examined the relationship between ecology and var-
and the dinosaurexhibit in the American MuseumofNat- iation in Cerion. Many of his students' themes were fa-
ural History in New York was a favorite destination. miliar, the relationships between ontogeny and phyloge-
Steve obtained his undergraduate degree in Geology at ny, and comparisons of punctuated vs. gradual patterns
Antioch College, and went on to graduate work at Co- of diversification. Where necessary, there was a sophis-
lumbia University, receiving his Ph.D. in 1967. However, ticated array of statistical and multivariate analyses to
the question he chose for his dissertation was not in deep quantify morphology and search for patterns through
time but rather in the shallow sand dunes of Bermuda. time. Steve often had an impressive multivariate meth-
Steve had become fascinated by the diversity of land odology in his own work (e.g., Gould, 1967, 1970,
snails there and in the Bahamas and he sought to under- 1984b) and his rigorous quantitative approach was mir-
stand their insular evolutionary patterns. Papers on Poe- rored in the work of many of his students.
cilozonites and Cerion soon followed, many co-authored It is also well known that Steve was not a "computer
with David—Woodruff. In 1984, Steve described his first geek," and many obituaries have commented on his
two species the Giant and Dwarf Smokestack Cerion avoidance of word processors and POPS compliant pro-
{Cerion excelsior Gould, 1984a, and Cerion caminiis grams. I also doubt that Steve ever navigated PAUP* or
Gould, 1984a, respectively). MacClade, but his own personal aversions never limited
From his study of Bahaman land snails Steve noticed his students' research programs; for example phylogenet-
that morphological evolution in Poecilozonites was not ic analyses were prominent in the work ofMorris (1991)
gradual; rather, large changes appeared suddenly, and and Yacobucci (1999).
these morphological reorganizations were short lived in Mollusks also served as exemplars in Steve's column
thefossil record and followed by another period ofstasis. "This View of Life" that appeared in the pages ofNat-
Another Columbia University graduate student had no- ural History Magazine. His commentaries dealt with nat-
ticed a similar pattern in the diversification of trilobites, ural history issues that ranged from hens' teeth to the
and after comparing notes they joined forces as Eldredge dating of the beginning of the millennium; and mollusks
& Gould (1972) to unleash punctuated equilibrium on a often graced those pages as well. In fact, the story of an
paleontological worl—d unaware ofits reliance on a cloven extinct little limpet once even found its way into a col-
hoofprint oftheory gradualism. To be certain, the pres- umn! However, the importance ofthose articles (and their
—
Notes, Information & News Page 357
afterlives in collected volumes) should not be underesti- turn ofthe last century and today. The malacological con-
mated for they translated the esoteric reports of our re- tributions and scope of work by Dall, Pilsbry, Berry, and
search into popularpieces thathave so farentertained and others in the early 1900s were enormous and often
educated two generations of lay naturalists. viewed as insurmountable by later workers. Up until
Although Steve's presence in the twenty-first century about 20 years ago, most American malacological polls
will be remembered as fleeting, this century will —be would have undoubtedly chosen one ofthese gentlemen's
marked by his greatest contribution, his magnum opus contributions as the most significant ofthe twentieth cen-
The Structure of Evolutionary Theory (2002). Steve's tury. Today the work of Gould and others has shown us
view of evolution as outlined in 1433 pages is (as it ever the potential of molluscan studies, and set new standards
was) pluralistic and hieratical, and for that he took sub- and expectations for modern malacological research.
stantial criticism from fundamental Darwinians and oth- However, I doubt that Steve will vie for first place at the
ers (Morris, 2001). Steve's ideas (as well as his prose) end of the current century. That spot will likely be re-
often exasperated some while inspiring others and this servedfor amalacologist whohas yettoundergo meiosis.
book is no different. David Wake (2002) has predicted We cannot predict where his or her future contributions
that The Structure ofEvolutionary Theory "... will be may lie. I suspect that assembling the unfalsified Mollus-
a permanent factor in the struggle to understand how life ca branch of the tree oflife or determining the regulatory
has evolved." Like Steve's other writings. The Structure cascades of the key innovations in the diversification of
ofEvolutionary Theory contains numerous mollusc—an ex- the molluscan bauplan will certainly occur in the next 98
amples supporting his view of the history of life from years. However, since we cannot know our future intel-
the punctuated evolutionary patterns of melanopsid spe- lectual descent's contingencies we have no way to predict
ciation to the spandrels of trochacean brooding. the directions ofthat future research. There—fore we might
Steve Gould's death on May 20, 2002, endedthecareer as welljust get on with the workbefore us Steve would
of the last century's finest malacologist, but his legacy to have it no other way.
malacology is immense. Steve never produced a classic
monograph or performed cladistic analyses that spawned Literature Cited
cascades of nomenclatural changes, and his name will
appear as taxon author on only a few leaves on the tree Allmon, W. D. 1988. Evolution and environment in turritelline
of life. Nevertheless, his contribution to our field tran- gastropods (Mesogastropoda, Turritellidae), lower Tertiary
scends all of these conventional measures. Steve showed ofthe U.S. gulfand Atlantic coastal plains (United States).
us how mollusks could be used to unravel the patterns Ph.D. Dissertation, Harvard University. 826 pp.
and processes of the last half a billion years of life, and Dall, W, H. 1877. On a provisional hypothesis ofsaltatory evo-
pwahtetenrncsu,rrSetnetvethweaorsiensotansdhymoadbeoluts pfraiolpeodsitongexnpelwainontehse.se Eldraleuldttgieoernn,.atNAi.vmee&rtiocSap.hnyJl.NeatGtioucruallgdir.satdu11a91l7:i2s1.m3.5P-u1Pnp3c.7t.u8a2t—e1d15equiinliTb.riJa.: Ma.n
In fairness, Steve was not the only one to travel down Schopf (ed.). Models in Paleobiology. Freeman, Cooper &
this path. His cohort includes such eminent colleagues as Company: San Francisco.
Michael Ghiselin—, Steve Stanley, and Geerat Vermeij Geary, D. H. 1986. The evolutionary radiation of melanopsid
malacologists all who have extended our collective vi- gastropods in the Pannonian Basin (late Miocene, eastern
sion beyond the usual taxon-based questions and practic- Europe). Ph.D. Dissertation, Harvard University. 238 pp.
es that we typically undertake. They took our (and their) Gould, S. J. 1967. Evolutionary patterns in pelycosaurian rep-
tiles: a factor-analytic study. Evolution 21:385-401.
favorite taxon and addressed abroad suite ofevolutionary Gould, S. J. 1970. Land snail communities and Pleistocene cli-
questions that provide insights into some ofthe processes mates in Bermuda: amultivariateanalysisofmicrogastropod
that have shaped the history of life on earth, cuul they diversity. Proceedings of the North American Paleontologi-
shuffle shells (and the shell-less) with the best of them. 1 cal Convention, Part E:486-52l.
observed Steve during a visit he made to Berkeley in Gould, S. J. 1971. Environmental control ofform in land snails:
1988 move effortlessly through our Cerion holdings, sug- a case of unusual precision. The Nautilus 84:86-93.
gesting mixed lots and re-identifying specimens. He also Gould, S. J. 1977. Ontogeny and Phylogeny. HarvardUniversity
Press: Cambridge, Massachusetts. 501 pp.
searched the vermetids for especially meandering speci- Gould, S. J. 1984a. Morphological channeling by structural con-
mens. Their openness intrigued him, rules were being straint: convergence in styles of dwarfing and gigantism in
broken, and the transition seemed to mark an important Cerion, with the description of two new fossil species and
yetunknown event in both their ontogeny andphylogeny. areportonthe discoveryofthelargestCerion. Paleobiology
He clearly understood and relished the value of museum 10:172-194.
collections and wasjust as accomplished there as he was Gould, S. J. 1984b. Covariance sets and orderedgeographic var-
iation in Cerion from Aruba, Bonaire and Curacao: way of
penning an introduction to a research paper that would studying nonadaptation. Systematic Zoology 33:217-237.
castAchatinella as the devil's advocate and the Rev. Gul- Gould, S. J. 2002. The Structure of Evolutionary Theory. Har-
ick as Mephisto (Gould, 1971). vard University Press: Cambridge. Massachusetts. 1433 pp.
One cannot help but notice the parallels between the HOAGLAND, E. 1975. Reproductive strategies andevolutioninthe
Page 358 The Veliger, Vol. 45, No. 4
genus Crepidula (Gastropoda: Prosobranchia). Ph.D. Disser- appeared to be P. johnsoni, and a description of its anat-
tation, Harvard University. 360 pp. omy is provided below. The species identification was
Morris, P. J. 1991. Functional morphology and phylogeny: an confirmed by comparison with the lectotype of P. john-
assessment of monophyly in the Kingdom Animalia and in
Paleozoic nearly-planispiral snail-like molluscs. Ph.D. Dis- soni deposited at the Natural History Museum, London
sertation, Harvard University. 435 pp. (BMNH) and examined by the senior author in 1995.
Morris, R. 2001. The Evolutionists; The Struggle for Darwin's For comparison, materials from the collections of D.
Soul. W. H. Freeman: New York. 262 pp. S. Brown (Pisidium ovampicum) and A.V. Korniushin {P.
OCKELMAN, N. 1964. Turtonki minuta (Fabricius), a neotenous milium) were used.
veneracean bivalve. Ophelia 1:121-146. All samples were preserved in alcohol. Anatomical
Rose, J. A. 1990. Cerion on San Salvador, Bahamas: ecology characters were observed under a stereomicroscope and
and intraspecific variation. Ph.D. Dissertation, HarvardUni-
versity. 149 pp. drawn with a camera lucida. Gill and mantle preparations
Stanley, S. M. 1972. Functional morphology and evolution of were processed according to Korniushin (1995).
byssally attached bivalve mollusks. Journal ofPaleontology Below a description of the anatomical characters and
46:165-212. a brief discussion ofthe possible relationships ofthe ex-
Wake, D. B. 2002. A few words about evolution. Nature 416: amined species are provided.
787-788.
Yacobucci, M. M. 1999. The evolutionary radiation ofacantho-
ceratid ammonites in the Cenomanian western interior sea- Pisidiumjohnsoni E.A. Smith, 1882
way ofNorth America. Ph.D. Dissertation, HarvardUniver- Material: Lectotype BMNH 82.3.5.23, 20 lieu (about 80
sity. 414 pp. km) from Tananarivu, Madagascar; FMNH 296604, 1 km
N of Ilempona, approx. 40 km NE of Antsirabe, Central
Madagascar, in a shallow ditch along railroad tracks, leg.
R. Webranitz 15 December 1989, 3 specimens.
Anatomical Description ofPisidiumjohnsoni Shell characters (Figures lA, B): Specimens FMNH
E.A. Smith, 1882 (Bivalvia: Sphaeriidae) 296604 corresponding with the published description
from Madagascar (Kuiper, 1966) and the lectotype.
A. V. Korniushin Adductor muscles: Posterior adductor small, oval (Fig-
National Museum of Natural History, B. Khmelnitsky ure IC). Anterior adductorbean-shaped, markedly shifted
str. 15, 01601 Kiev, Ukraine; [email protected] upward (dorsally).
and
Mantle: Mantle edge thickened by strong development
J. Gerber
of longitudinal muscles (Figures IC, F). Presiphonal su-
Department of Zoology, Field Museum of Natural ture markedly elongated, longer than pedal slit. Inner ra-
History, 1400 S. Lake Shore Drive, dial mantle muscles arranged in four strong and clearly
Chicago, @Illinois 60605, USA; defined bundles, three of them (anterior) placed at edge
jgerber fieldmuseum.org
ofpedal slit close to each other, posterior bundle at distal
Kuiper (1966) reported five species of the genus Pisidium end of presiphonal suture.
C. Pfeiffer, 1821, from Madagascar, one of them [P. cas-
Gill: Outer demibranch placed at tenth filament of inner
ertanum (Poli, 1791)] being cosmopolitan, two {P. ovam-
one (two specimens examined). Brood pouch in low po-
picum Ancey, 1890, and P. viridarium Kuiper, 1956) rep-
sition (Figure ID), formed by four filaments of inner de-
resenting the African fauna, and two {P. johnsoni E.A.
mibranch and partly covered by the inner (ascending) la-
Smith, 1882, andP. betafoense Kuiper, 1953) being restrict-
mella. Three large larvae found in each ofstudiedpouches.
ed to the island. P.johnsoni was the mostinteresting among
these species, since its similarity to the Holarctic P. milium Nephridium: Open type (pericardialductvisiblebetween
(Held, 1836) was noted (Kuiper, 1966). However, no ana- branches ofdorsal lobe), dorsal lobe quadrangular(Figure
tomical dataon the species were available until now, where- IE).
as soft body characters have proved to be ratherinformative
Remarks: The elongated presiphonal suture and very
for the systematic and phylogenetic studies in Palearctic and
short pedal slitwere noticeable also in the dried softbody
African Sphaeriidae (Korniushin, 1998a, b).
of the lectotype (Figure IG).
Recently, we examined a sample from Central Mada-
gascar, now deposited in the Field Museum of Natural Pisidiumjohnsoni has a very peculiar anatomy and is
History. Chicago (FMNH), containing two Pisidium spe- distinctly different from other species of Pisidium. How-
cies. One of the species (FMNH 296603) was identified ever, it is similar to the Holarctic P. milium (see Korni-
as P. viridarium, and its anatomical characters were in ushin, 1996) in its very short pedal slit, in addition to the
good agreement with those reported inthe literature (Kor- shell characters reported by Kuiper (1966). A similar
niushin, 1998b). The other species (now FMNH 296604) anatomy was also reported for the Madagascar and Af-