Status of some names associated with the salt marsh greenhead fly, Tabanus nigrovittatus Macquart (Diptera: Tabanidae) in eastern Coastal North America and lectotype designation for Tabanus conterminus Walker


Burger, J.; Sofield, R.; Freeman, J.

Annals of the Entomological Society of America 78(1): 12-13

1985


Recent studies have demonstrated that Tabanus nigrovittatus Macquart, the Atlantic coastal salt marsh greenhead fly, consists of a complex of at least two distinct species. Stepwise discriminant analysis of four morphological characters of T. simulans Walker and T. conterminus Walker type specimens showed that T. conterminus is the second species in the complex in northeastern salt marshes. T. simulans is conspecific with T. nigrovittatus.

Status
of
Some
Names
Associated
with
the
Salt
Marsh
Greenhead
Fly,
Tabanus
nigrovittatus
Macquart
(Diptera:
Tabanidae)
in
Eastern
Coastal
North
America
and
Lectotype
Designation
for
T.
conterminus
Walker
JOHN
F.
BURGER,'
ROY
K.
SOFIELD,
2
AND
JEFFREY
V.
FREEMAN
3
Ann.
Entomol.
Soc.
Am.
78:
12-13
(1985)
ABSTRACT
Recent
studies
have
demonstrated
that
Tabanus
nigrovittatus
Macquart,
the
Atlantic
coastal
salt
marsh
greenhead
fl
y,
consists
of
a
complex
of
at
least
two
distinct
species.
Stepwise
discriminant
analysis
of
four
morphological
characters
of
T.
simulans
Walker
and
T.
conterminus
Walker
type
specimens
showed
that
T.
conterminus
is
the
second
species
in
the
complex
in
northeastern
salt
marshes.
T.
simulans
is
conspecific
with
T.
nigrovittatus.
RECENT
INVESTIGATIONS
on
the
ecology
(Freeman
and
Hansens
1972),
enzyme
electrophoresis
(Ja-
cobson
et
al.
1981),
behavior
(Graham
and
Stof-
folano
1983a,b),
and
morphology
(Sofield
et
al.
1984)
of
eastern
salt
marsh
greenhead
horseflies
have
shown
conclusively
that
two
distinct
species
of
salt
marsh
greenhead
fl
ies
exist
in
eastern
coastal
salt
marshes.
Less
clear,
however,
was
the
name
that
should
be
applied
to
the
recently
recognized
second
taxon
related
to
Tabanus
nigrovittatus
Macquart.
Recent
development
of
a
morphomet-
ric
discriminant
analysis
(Sofield
et
al.
1984)
has
allowed
us
to
analyze
directly
the
type
specimens
of
T.
simulans
Walker
and
T.
conterminus
Walk-
er
and
to
determine
that
the
latter
represents
the
second
taxon.
Macquart
(1847)
described
T.
nigrovittatus
from
a
female
from
Nova
Scotia.
A
specimen
labeled
as
,<
cotype"
of
nigrovittatus
in
the
British
Museum
(Natural
History)
(BMNH)
bears
a
Panama
label
and
is
probably
T.
trivittatus
F.
or
a
close
relative
(Burger
1984).
The
type
of
T.
nigrovittatus
thus
must
be
presumed
missing.
However,
because
Macquart's
original
description
of
nigrovittatus
agrees
well
with
that
of
the
species
common
in
eastern
salt
marshes,
the
name
is
probably
cor-
rectly
applied.
Walker
(1848)
described
T.
simulans
from
a
single
female
(in
the
BMNH)
from
Nova
Scotia.
He
described
T.
conterminus
from
two
female
syntypes
from
unspecified
localities
in
the
United
States.
The
smaller
(13.2
mm)
of
the
two
females
is
hereby
designated
as
lectotype'
of
T.
conter-
minus
and
is
so
labeled.
The
'paralectotype'
fe-
male
is
14.2
mm
long.
Both
specimens
are
depos-
ited
in
the
BMNH.
Until
recently,
both
taxa
were
'
Dept.
of
Entomology,
Nesmith
Hall,
Univ.
of
New
Hamp-
shire,
Durham,
03824.
Tennessee
Temple
Univ.,
Chattanooga,
37404.
Dept.
of
Natural
Sciences,
Castleton
State
College,
Castleton,
VT
05735.
12
considered
synonyms
of
T.
nigrovittatus
(Philip
1965).
Hine
(1906)
examined
the
type
specimens
of
both
T.
simulans
and
T.
conterminus
and
consid-
ered
the
latter
specifically
distinct
from
T.
nigro-
vittatus.
His
basis
for
this
distinction
was
size
(9-
11
mm
for
nigrovittatus;
12-14
mm
for
conter-
minus)
and
the
size
of
the
male
head,
including
eye
facet
configuration.
He
also
mentioned
that
the
thorax
of
conterminus
was
steel
gray,
rather
than
yellowish
gray
as
in
nigrovittatus.
Hine
pre-
sciently
stated
that
"when
the
males
of
the
species
of
the
Atlantic
Coast
are
brought
together,
it
is
certain
that
there
are
two
species
in
what
has
gone
under
the
name
of
T.
nigrovittatus
. . .
."
Stone
(1938)
examined
specimens
that
Hine
had
compared
with
the
types
of
simulans
and
conter-
minus,
but
did
not
examine
the
types
themselves.
This
is
unfortunate
because
he
considered
simu-
lans
and
conterminus
to
be
conspecific
and
both
to
be
synonymous
with
nigrovittatus.
He
also
stat-
ed
that
if
varietal
rank
were
to
be
assigned
to
either
simulans
or
conterminus,
that
simulans,
being
the
older
name
(page
priority),
would
apply
to
the
distinct
form.
Subsequent
authors
have
followed
Stone's
inter-
pretation
of
nigrovittatus
synonymy.
Pechuman
(1981)
stated
that
a
larger
form
of
nigrovittatus
with
a
grayer
mesonotum
and
a
greater
extension
of
large
eye
facets
in
the
male
was
T.
simulans
(=conterminus),
following
Stone's
belief
that
both
were
conspecific
with
nigrovittatus.
However,
it
was
conterminus
that
Hine
considered
the
larger,
grayer
species.
Freeman
and
Hansens
(1972),
in
an
ecological
study
of
salt
marsh
breeding
Tabanidae,
found
lar-
vae
that
were
noticeably
different
from
T.
nigro-
vittatus.
They
called
these
larvae
"Tabanus
species
3."
Adult
females
reared
from
these
larvae
were
larger
than
nigrovittatus
and
the
eyes
of
males
were
like
those
of
T.
conterminus.
Larvae
of
Ta-
January
1985
BURGER
ET
AL.:
STATUS
OF
SALTMARSH
HORSE
FLY
NAMES
13
banus
species
3
also
occurred
mainly
in
tall
grass
areas
adjacent
to
drainage
ditches,
whereas
ni-
grovittatus
larvae
occurred
more
frequently
in
the
short
grass
open
marsh.
Freeman
and
Hansens
(1972)
suspected
that
these
larger
fl
ies
might
rep-
resent
a
distinct
species.
Jacobson
et
al.
(1981),
using
starch
gel
electro-
phoresis,
found
that
adult
T.
-
nigrovittatus"
from
four
localities
in
New
Jersey
could
be
separated
into
two
distinct
breeding
groups
based
on
elec-
tromorph
differences
encoded
by
three
gene
loci,
thereby
conclusively
establishing
the
existence
of
two
distinct
species
in
the
T.
nigrovittatus
com-
plex
in
New
Jersey.
Graham
and
Stoffolano
(1983a)
studied
the
ovi-
position
habits
of
T.
"nigrovittatus"
in
Massachu-
setts
and
found
that
caged
fl
ies
<12
mm
long
laid
only
gray,
tiered
egg
masses
while
fl
ies
.14
mm
laid
only
tan,
shingled
egg
masses.
They
concluded
that
two
distinct
species
were
present
in
Massa-
chusetts
salt
marshes.
Unfortunately,
they
fol-
lowed
Stone's
interpretation
of
nigrovittatus
syn-
onymy
and
designated
the
second,
larger
species
that
laid
tan,
shingled
egg
masses
as
T.
simulans,
without
reference
to
type
material.
Because
of
morphological
variation
in
the
T.
nigrovittatus
complex,
it
normally
would
be
dif-
ficult
to
determine
what
name
is
properly
applied
to
the
second,
larger
species
found
in
Atlantic
coastal
salt
marshes.
However,
Sofield
et
al.
(1984)
used
a
stepwise
discriminant
analysis
of
16
mor-
phometric
characters
and
identified
a
suite
of
four
traits
that
in
combination
separate
the
two
species
in
New
Jersey
without
error.
A
simple
taxonomic
key
uses
total
body
length
and
three
head
char-
acters
to
accomplish
this
discrimination
as
follows:
1.
Total
body
length
<10.7
mm
nigrovittatus
Macquart
Total
body
length
mm
2
2.
Total
body
length
-13.8
mm
conterminus
Walker
Total
body
length
<13.88
mm
3
3.
Canonical
score'
>0.30
nigrovittatus
Macquart
Canonical
score
<0.30
.
.
conterminus
Walker
This
analysis
was
applied
to
the
holotype
of
T.
simulans
and
the
lectotype
and
paralectotype
of
T.
conterminus.
The
canonical
value
for
the
sim-
ulans
holotype
was
well
within
the
range
observed
for
T.
nigrovittatus,
while
the
canonical
values
for
both
conterminus
specimens
were
well
within
the
range
for
the
second
species
of
the
nigrovittatus
complex.
The
correct
name,
therefore,
for
Tabanus
species
3
of
Freeman
and
Hansens
(1972),
Group
II
of
Jacobson
et
al.
(1981),
and
T.
simulans
sensu
Gra-
ham
and
Stoffolano
(1981a),
is
T.
conterminus
'
Canonical
score
=
17.09
-
(28.84)
x
WFDOR
-
(22.38)
x
WSCAP
+
(5.88)
x
WHD
-
(1.45)
x
TOTLEN,
where
WFDOR
=
width
of
frons
at
vertex
(mm);
WSCAP
=
width
of
scape
at
apex
(mm);
WHD
=
width
of
head
at
widest
point
(mm);
TOTLEN
=
total
body
length
(mm).
Walker.
Tabanus
simulans
is
conspecific
with
T.
nigrovittatus.
We
suspect
that
T.
conterminus
may
occur
from
Nova
Scotia
to
Florida
and
possibly
along
the
Gulf
Coast
as
well
and
that
it
may
be
more
abundant
in
the
southern
part
of
its
range.
A
distributional
study
of
the
nigrovittatus
com-
plex
is
in
progress.
Acknowledgment
We
thank
Robert
C.
Vrijenhoek,
Rutgers,
The
State
Univ.,
for
his
critical
review
of
an
earlier
version
of
this
paper
and
for
many
helpful
comments
;
and
Paul
C.
Johnson
and
Donald
S.
Chandler,
Univ.
of
New
Hamp-
shire,
for
their
review
and
comments
on
the
manuscript.
This
article
is
Scientific
Contribution
No.
1300
from
the
N.H.
Agric.
Exp.
Stn.
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