Neidium rudimentarum (Bacillariophyceae), a rare species with novel rudimentary canals and areolar openings from the temperate region of North America

2004·4.4 MB·English

by  P B Hamilton

RHODORA,
Vol. No. 925, 33-42, 2004
106,
pp.
NE/DIUM RUDIMENTARUM (BACILLARIOPHYCEAE), A RARE
WITH NOVEL RUDIMENTARY CANALS AND
SPECIES
AREOLAR OPENINGS FROM THE TEMPERATE REGION
OF NORTH AMERICA
Paul Hamilton
B.
Museum
Research Division, Canadian Nature,
oi'
KIP
P.O. Box 3443. Station D. Ottawa. Ontario. 6P4, Canada
[email protected]
e-mail:
Peter A. Siver
Botany Department. Connecticut College.
New CT
London. 06320
[email protected]
e-mail:
W.
Charles Reimer
The Academy
of Natural Sciences of Philadelphia,
PA
and Parkway. 19103
19th the Philadelphia.
e-mail: [email protected]
abstract. Neidium rudimentarum a rare species identified from only two
is
localities in the United States. Rudimentary canals on either side of the valve, that
J
pm
extend 10-25 from the terminal apices, are unique to this species within the
genus. At the internal termination point, the canals open into chambered areolae that
form a well-developed matrix of interconnected chambers. In addition to the canals,
The
linear are unique for the external opening of the areolae. type locality
slits
New
Bluehole pool/1 nskip River, Jersey a cool-water, oligotrophia system with
is
groundwater source from Potomac-Raritan-Magothy Neidium
a the aquifer.
known
hamatum, from Rio Tapajos, Brazil the closest taxon general
is in
morphology, however has complete longitudinal canals extending from apex to
it
The
apex. rudimentary canal of this species is in distinct contrast to the multiple
canals of N. tumescens and thus far unique within the genus Neidium sensu lata.
is
Key Words: diatom, North America, rare species, rudimentary canal
Neidium Neidium rudimentarum, was
In 1959, an interesting species,
described with longitudinal bands (canals) present only the apices
at
(Reimer 1959). This incomplete or rudimentary canal formation
is
unique to this species, especially considering that the primary character
Neidium
for the presence of longitudinal canals extending along the
is
valve margin. The observed occurrence from two localities in the United
States [New Jersey, Winslow, Blue Hole, Inskip River (Boyer
New
Collection, W-6-23, ansp) and Hampshire, Grafton County, Crane
33
34 Rhodora
Vol. 106
I
Pond {(i.C. 53811b, ansp)] also of interest, given the extensive
is
collecting of diatoms across North America from both livins and
historical sediments. This study examines the morphological structure of
N. rudimentarum and compares related taxa within the genus.
to
it
Further, the diversity of canal structures explored with reference to the
is
morphology o( genus Neidium sensu
the
lato.
AM) MHTHODS
MATERIALS
Specimens o( Neidium rudimentarum from the holotype slide
ER-W
(BOY
-6-23, ansp) were observed and measured using Wild
a
M20
microscope equipped with bright field optics. In addition, type
Academy
material was acquired for examination from the of Natural
K
Sciences (ansp). The type material was mounted using Hyrax and
Museum
deposited the Canadian of Nature under 68356 (cana).
at
Morphometric observations were made on 68356 cana with
the slide
(LM)
a Leitz Dialux 22 microscope equipped with bright field and
phase Subsamples from were
contrast optics. the type material also
mounted scanning microscope (SEM) examination
for electron
An
following the procedures of Hamilton (1990). Hitachi S-530
et al.
SEM SEM
XL30
and a FEI Environmental were used to study detailed
morphometric structure using acceleration voltages ranging from 5-15
Anonymous
kV. Diatom terminology follows of Ross
that (1975),
et al.
(1979), and von Stosch (1975).
RRSWLTS
Neidium rudimentarum Reimer, emend. Acad.
Proc. Nat. Sci.
New
Philadelphia 111: 1-35. 1959. Type: Jersey: Winslow,
ii.s.a.
May
Blue Hole, Inskip River, 26 1923, T.C. Palmer (holotype:
BOY ER-W
Boyer Collection, -6-23, ansp; subsamples of type
material: 68356, cana).
pm
Valves 52-1 1-20
linear to linear-elliptical, 10 jam in length, in
1
pm
19-24 12-18
width, 10 \xm with areolae 10 (Figures
striae in in
1-5). Apices are obtusely rounded to subcuneate. The raphe filiform
is
with deflected central raphe ends that do not terminate in distinct fissures
The
(Figures terminal raphe fissures are partially covered with
3, 5).
1,
LM
which
an apical flap (lacinia), appears as a "bifurcation" of the
in
terminal raphe end (Figure The central area round to slightly
1). is
27-40%
elliptical, covering of the valve width. Striae around the central
area exist as slits that extend towards the valve mantle. The uneven
—
Hamilton Neklium rudimentarum
35
2()04| et al.
1
* *
—
-
<
I,* ::*"«r<3
-
t# . I j
10
fjm
LM
Figures L-5. Line drawing and photomicrographs of Neidium rudimentarum.
&
Lino drawing of the holotype printed with permission from Roimer in Patrick
I.
Reimer (1966). 2-5. Bright Field light micrographs taken from 68356, cana (two
slides).
spacing of areolae, especially evident along the valve margin, creates
"wavy
around
a orientation of these pores, especially the central area
Two
from and
(Figures 1-5). longitudinal canals originate the apices
quickly terminate 10-25 from the apex (Figures 1-4). Striae are
|Jin
slightly radiate at the center to slightly convergent at the apices. This
emended
species description differs from the original (Reimer 1959) by
expanding the size range, increasing the stria count, introducing an
areola count, and clarifying the ultrastructure of the longitudinal canal
and
areolae.
many
shows from
Externally, the valve structural characters that differ
other Neidium species (Figures 6-13). The raphe composed of two
is
straight branches running the length o( the valve and sits on a solid
Rhodora
36
Vol. 106
SKM.
Figures 6—13. Ncidium rudimentarum, external surface valve structure. 6.
A
Whole
valve. raised central area with isolated depressions and clearly hooked
7.
raphe endings. 8. Central area. 9. Girdle view of frustule apex, single arrow indicates
shows
the ligula, double arrow the poroid pores on the pars exterior of a pleura. 10.
Central area with raised axial area. 11. Apex, mantle projection showing
a longitudinal canal starting from apex and ending early along the valve margin,
arrow indicates termination point of canal. 12. Apex, valve projection showing the
complete Apex,
longitudinal canal. 13. terminal projection highlighting the basal
—
Hamilton Neidium rudimentarum 37
2004]
et al.
(non-ornamented) axial area, which elevated at the terminal apices
is
(Figures The axial area the center of the valve also
6, 9, 11, 12). at is
elevated and surrounded by a depressed central area (Figures
7, 8, 10).
The raphe terminates the mantle under a small but distinct lacinia that
at
composed
extends to the mantle base (Figures 9, 13). Striae are of linear
which become rounded along
areolae, slightly to elliptical the
slit-like
Long
along
mantle face (Figures 7, 8, 10, 11 elliptical areolae also exist
).
Around
the base of the mantle the apices (Figure the central area,
at 13).
the set of areolae are lineolatc and oriented perpendicular to other
first
LM
The
areolae creating the slits observed in (Figures 8, 10). central
area clearly elevated and may sometimes have depressions, which are
is
When may
not areolae (Figure the valve deteriorates, the areolae
8).
become The does
round appearance (Figure longitudinal canal
in 11).
two more
not extend far from the apices and terminates into or areolae
(Figures Three to four pleurae are typically present with
6, 11, 12).
a complete frustule. The pleurae are incomplete ligulate bands opening
alternately the apices (Figures Each pleura has one row of
at 9, 13).
pores along the upper pars exterior edge.
Internally, the raphe elevated on the sternum, ending terminally in
is
hclictoglossae and centrally with a bimodal central nodule (Figures 14,
The
The raphe key and formation. small longitudinal
a slot
15, 16). is
open through enlarged
canals the apices internally elliptical slits that
at
The
are especially evident at the apex (Figures 15, 17). equally spaced
areolae are round to elliptical with beveled edges, creating a poroid
The composed chambers
internal surface. areolae are o\ small internal
valve and connect other adjacent areolae
within the siliceous structure to
and the longitudinal canal (Figures 14, 16. 18, 19). Other taxa with this
Neidium
type of open-chambered or interconnected areolae include
Krammer,
amphigomphus (Ehrenb.) N. ampliation (Ehrenb.) N.
Pfitzer.,
gracile Hust, N. hitchcockii (Ehrenb.) Cleve, and N. tumescens
(Grunow) Cleve (Hamilton 1995; Rcichardt 1995; Siver
et al. et al.
No hymen were found on few
2003; unpubl. images). structures the
however presumed hymens would be
specimens observed, that
is
it
present and cover the internal openings of the areolae. This assumption
hymens Neidium
based on the consistent presence of in other taxa
is
with a similar areolate structure.
<
areolae along the mantle, the lacinia partially covers the terminal raphe ending. Note:
on specimens scale measures are subject to error.
tilted tilt
Rhodora
38
Vol. 106
SEM,
Figures Neidium rudimentarum,
14 c internal surface valve structure.
).
l
14. Major proportion of valve, with large round areolae. 15. Apex showing the
rudimentary and
canal large elliptical openings: insert highlights the helictoglossa.
16. Central nodule, areolae slit-like around the central area with bimodal formation
created by two adjacent helictoglossae. 17. Apex, internal valve projection.
termination of the longitudinal canal is cleaiiv visible. 18. Broken valve illustrating
A
chambered
the nature o\' the areolae. 19. depressed region around each areola
(arrow). Note: on specimens measures
tilted scale are subject to error.
tilt
GEOLOCY and The New
rcology. geology
of the Jersey Coastal Plain
along the Great Egg Harbor River Quaternary the coastal outflow
is at in
County Upper The
Atlantic to Tertiary the headwaters.
in surficial
sediments are generally sand and gravel deposits Great Egg Harbor
at
outflow to sand and green sands the southern Gloucester County
in
The
hydrogeology
region. loeal a unique part of the Potomac-Raritan-
is
Magothy
Aquifer system and The
(Gill Farlekas 1976). aquifer
is
Camden
productive Gloucester and Counties 50
in (ca. billion litres of
available water measured during 1967) and can be classified as a leaky
and
artesian aquifer (Gill Farlekas 1976).
—
Hamilton Ncidium rudimentarum 39
20041
ct
al.
The Great E22 Harbor River flows from the headwaters within the
Potomac-Raritan-Magothy system Winslow
aquifer of the Wildlife
Management Area County) Egg Harbor Bay
(Gloucester Great
to
at
New
The
Corbin City (Atlantic County), Jersey. river, west of
m
Hanington and south of Berlin Blue Hole pool 15-25 wide,
at is
m
and 1-2 deep, with a predominantly sand cobble bottom. The original
New
sample by Palmer
collected T. C. lists the collection site as Jersey,
Winslow, Blue Hole, Inskip River. Although the description
site
is
incomplete, the type locality clearly Blue Hole (39°37.584 / N,
is
Egg
74°53.279'W), on west of Great Harbor River
located the side
Winslow Management
immediately
within the Wildlife Area, adjacent
Road.
Cecil Inskip
to
A
newspaper unknown)
small article written in a local (author
suggests that Blue Hole pool an "ice" cold water pool, separated from
is
m
the river by a 15 bank, with the possibility of occasional spring
m m
40-50
flooding. Blue Hole pool approximately long, 25 wide and
is
m
The
up to 3 deep. water clear, with light easily penetrating to the
is
bottom. The blue appearance of the water enhanced by the reflection
is
of light from the while diatomaceous earth and siliceous sediment at the
bottom the pool. The water analysed on October 27, 2003 was acidic
in
(pH 4.3), with a low conductance (44 |iS/cm). Allochthonous organic
input to the pools (significant leaf accumulation within the near-shore
was
zone) clearly evident. Other taxa observed at this site of potentially
poorly buffered oligotrophic water include Asterionella var.
cf. ralfsii
americana Korner, Aulacoseira canadensis (Hust.) Simonsen, Brachy-
neoacuta Lange-Bert., Eunotia zygodon Ehrenb., Frustulia
sira
De
rhomboides (Ehrenb.) Toni, Ncidium (Ehrenb.) N.
Plitzer,
affine
and
tumescens, N. ampliation.
DISCISSION
margin
Longitudinal canals alone the valve are the defining
O O
<D C?
morphological structures for the genus Ncidium. These canals can vary
>10
from one chambers running along each margin (Figures
to parallel
21, 22, 23). Single canals can be large and elevated like a keel (e.g.,
and
N. hitchcockii, N. gracile) or small within the valve silica matrix
&
from
hard distinguish adjacent areolae N. coralieae Metzeltin
to [e.g.,
Krammer, Ncidium rudimentarum
N. catariense (Krasske) Lange-Bert.].
uniquely lacks a single complete longitudinal canal. Although not
complete, rudimentary canal easily visible with a morphological
this
is
&
hamatum Krammer
structure similar to N. ampliatum and N. Metzeltin
*
*
I
40 Rhodora
Vol. 106
I
23
21
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:
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* . *
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*
* • *
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-
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*
*
I * P
. - .
| * '-Ti
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» . —
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* *
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-
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!•?
:
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i * ^
*--
* *
•
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" / .
!•
pm
50
Figures 20-23. Sonic Neidium species highlighting differences among the laxa.
Neidium hamatum, morphology
20. ampliation. 21. Ncidiu/n similar with
in
a complete longitudinal canal from apex lo apex. 22. Neidium bergii with lineate
areolae around the central area. 23. Neidium tumescens, illustrating the presence of
multiple canals adjacent to each other along the margin.
-
—
Hamilton Neidium rudimentarum
41
et
2()()4| al.
(Figures 20, 21). The areolae are also distinct slits on the external valve
SEM
known
face whereas other species identified by exhibit simple
all
poroid to elaborate volae-covered areolae (Hamilton 1995. 1996;
et al.
Metzeltin and Lange-Bertalot 1998; Siver 2003). Even though
et al.
it
lacks a complete canal and rounded externally opening areolae, taxon
this
clearly belongs within the genus because contains other typical
it
characters including the presence of deflected proximal raphe endings and
two
laciniae at the apices. In general outline, taxa are similar to N.
hamatum However
rudimentarum: N. and N. ampliatum sensu these
lata.
both have a well-developed complete longitudinal canal along each
The morphology hamatum
margin. almost identical of N. especially
is
Amazon,
interesting because this taxon reported as a fossil in the Brazil,
is
and may have some association with N. rudimentarum, which an
it is
km
isolated endemic species less than 4,000 to the north (Figure 2 The
).
1
areolae around the central area and the undulating appearance of
slit-like
the areolae from apex to apex are also similar to structures observed in N.
Krammer
The
bergii (A. Cleve) (Figure 22). significance of this similarity
rudimentarum most Neidium
not Ecologically, N. similar
clear. to
is is
species preferring low pH, low conductance, and an organically rich
benthic
habitat.
The genus Neidium covers a large morphological range of canal types
>10
from one rudimentary canal rudimentarum) well-developed
to
(A',
The
canals tumescens, Figure 23). diversity of forms within the
(TV.
may some
genus and the morphological variability o! the species have
and
implications understanding the significance of longitudinal canals
in
many
keels which are observed genera within the Bacillariophyceae,
in
both marine and freshwater.
CAN-RAC
acknowledgments. This work was funded by grant
a
We
P.B.H. thank K. Ponader held assistance while collecting
to for in
New
Jersey.
cued
literature
Anonymous. 1975. Proposals for a standardization of diatom terminology and
Nova 323-354.
diagnoses. Beih. Hedvviizia 53:
Gill, H. E. and G. M. Farlekas. 1976. Geohydrologic Maps of the Potomac
New
Raritan-Magothy Aquifer Syslem the Jersey Coastal Plain, HA-557.
in
New
State of Jersey, Dept. of Environmental Protection, Trenton, NJ.
Hamilton, McNeely, and M. The morphology and
P. B., R. Poulin. 1996.
distribution of Neidium distincte-punctatitm Ilustedl and systematic position
its
Diatom 59-71.
within the genus. Res.
I:
I
42 Rhodora
[Vol. 106
—
M. Poulin, and M. C. Taylor. 1990. Neidium alpinum var. quadripuncta-
,
turn (Hustedt) comb, now, an important acidobiotic taxon from Northeastern
North America. Diatom Res. 289-299.
5:
—
and D. Walker. 1995. Neidium hitchcockii (Ehrenbenj) Cleve,
, ,
a morphologically complex taxon within the genus Neidium (Naviculars.
A
61-77. Kociolek and M.
Bacillariophyta), Sullivan,
pp. In: J. P. J. eels.,
A
Century of Diatom Research North America: Tribute to the Distinguished
in
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Champaign.
IL.
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I.
About 700 predominantly rarely known or new taxa representative of the
neotropical flora. Iconographia Diatomologica, Vol. 5. H. Lange-Bertalot. ed.
Koelt/ Scientific Books, Konigstein, Germany.
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1.
Ri.k iiardt, E. 1995. Die diatomeen (Bacillariophyceae) Ehrenbergs material von
in
Cayenne, Guyana Gallica (1843). Iconographia Diatomologica, Vol. H.
I.
Lange-Bertalot. Koeltz Books, Konigstein, Germany.
ed. Scientific
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I.
taxonomic revisions. Proc. Acad. Nat. Sci. Philadelphia III: 1-35.
Ross, R., E. Cox, N. Karayeva, D. G. Mann, T. B. B. Paddock, R. Simonsen,
J.
I.
and P. A. Sims. 1979. An amended terminology for the siliceous components of
Nova
diatom Iledwigia 513-533.
the 64:
cell.
Siver, A., B. Hamilton, K. Stachura-Suchoples, and Kociolek. 2003.
P. P. J. P.
Morphological observations of Neidium species with arrowhead-shaped valve
apices, including the description of a new species. Diatom Res. 18: 54—68.
von An amended Nova
STOSCH, H. A. 1975. terminology diatom
the girdle.
o\'
Hcdwieia 53: 1-35.