1997 NORTHEASTERN NATURAUST 4(4): 231-236
MACROBDELLA SESTERTIA (HIRUDINEA:
HIRUDINIDAE) IN MAINE AND A KEY TO THE
HIRUDINIFORM LEECHES OF MAINE
DOUGLAS G. SMITH * AND SHANE HANLON **
Abstract -Macrobdella sestertia, a large rare leech, is reported from Maine for
the first time. Prior to the Maine specimen, the species was known only from
four specimens collected in Massachusetts. Currently, a total of four
hirudiniform leech species, including the common but pr~viously unreported
Haemopis marmorata, are known from the state and are included in a key to
hirudiniform species of Maine.
One of the rarest leech species in North America is Macrobdella
sestertia Whitman 1886, a large leech closely related to the common and
widespread Macrobdella decora (Say, 1824). Both species are armed
with powerful tooth bearing muscular jaws ideally suited for piercing
skin (Fig. I). The more common M. decora is sanguinivorous and preys
chiefly on aquatic vertebrates such as frogs and salamanders (Sawyer,
Figure 1. Scanning electron micrograph of apex of jaw of M. sestertia. Teeth
located within open pockets of tissue. Scale equals 0.05 mm.
* Department of Biology. University of MA, Amherst, Massachusetts 01003-5810 and
Museum of Comparative Zoology, Harvard University, Cambridge, MA 01238; ** De-
partment of Biology, University of Massachusetts, Amherst, MA 01003-5810, Current
address: Department Fisheries and Wildlife Sciences, Virginia Polytechnic Institute and
State University, 106 Cheatum Hall, Blacksburg, V A 24061-0321
232 Northeastern Naturalist Vol. 4, No.4
1972) and has been reported to attack nearly any vertebrate that enters
water (Sawyer, 1972). It even preys on fish. In Maine, Rupp and Meyer
(1954) reported an outbreak of leeches in Quinby Pond, Rangeley, that
affected the resident brook trout population. M. sestertia presumably
has similar habits.
Fish survey work conducted in Maine by the U.S. Environmental
Protection Agency for the environmental Monitorinng and Assessment
Program (EMAP), Surface Waters-Lakes has produced a collection of
several specimens of hirudinform leeches, which are the largest and
most conspicuous leech species of the New England leech fauna.
Among the collection is a specimen of M. sestertia, representing the
first record from Maine and only the fourth specimen collected in this
century. The present report reviews the distribution of this species and
provides a key to the hirudiniform leeches of Maine.
MA TERIALS AND METHODS
The leech specimens were collected from 1991 to 1996 during EMAP
fish surveys by seining, trapping, and electro-fishing. Additional speci-
mens for study were collected by the junior author (Hanlon) during field
work conducted in 1996. The M. sestertia specimen was collected by
EMAP personnel on 12 July 1993 from Mill Brook Pond, Sebec Lake,
Piscataquis County. Mill Brook Pond is a small isolated pond with
oligotrophic features situated about 200 M in elevation (T, Whit tier ,
pers. corn.). All EMAP fish specimens were field fixed in 10% formalin,
including the leech specimens without relaxation. The Hanlon specimens
were either field preserved without relaxation or narcotized in beer and
then fixed in 10% formalin. All specimens were eventually transfered to
50% isopropyl alcohol and divided between the University of Massachu-
setts Museum of Zoology invertebrate collections (UMA) and Harvard
University Museum of Comparative Zoology invertebrate collections
(MCZ). The specimen of M. sestertia has been deposited into the Univer-
sity of Massachusetts collection (UMA AN.431). Specimens were dis-
sected with the aid of a Wild M5 dissecting microscope. Scanning
electron microscopy was accomplished with a JEOL Model JSM 5400
scanning electron microscope.
A review of the taxonomy and known distribution of M. sestertia
was provided by Smith (1977) who reported on two specimens (UMA)
collected in northeastern Massachusetts. Subsequently, a third subadult
specimen was collected in the Herring River, Harwich, Massachusetts
(Smith, UMA unpub. record) bringing the total number of specimens
collected to three since Whitman's (1886) original description. Only
1997 D. G. Smith and S. Han1on 233
one pre-1900 specimen illustrated in Sawyer (1972) exists in the MCZ.
The Maine specimen, the fifth in existence, was preserved without
relaxation and was greatly contracted, however, it is clearly an adult and
shows the external reproductive features typical of M. sestertia. Nearly
nothing is known about the ecology of this species and to date M. decora
has not been found with M. sestertia. EMAP personnel indicated in
notes to T. Whit tier that leeches were present in Mill Brook Pond but the
single specimen of M. sestertia was all that they collected. Smith (1977)
suggested the the species geographical range is throughout the coastal
region of New England, and the Maine record supports this contention,
except that the Maine locality is farther inland than previous records.
Sawyer (1986) revised the worldwide leeches and within the large
Order Arhynchobdellida, he recognized the Hirudiniformes, a suborder
including several families, two of which, the Haemopidae and the Hiru-
dinidae, occur in northern New England. The Hirudinidae includes the
genus Macrobdella, the feeding habits of which have been discussed
above. The Haemopidae are chiefly predators of other invertebrates but
will also attack small vertebrates. Haemopids have muscular jaw-like
ridges in the pharynx and most species have teeth (Fig. 2), but a few
species are edentulous. Haemopis grandis has been previously reported
Figure 2. Row of teeth from H. marmorata jaw. methylene blue. Scale equals
234 Northeastern Naturalist Vol. 4, No.4
from Maine (Rupp and Meyer, 1954; Klemm, 1985) and is the largest
species of leech in the Maine fauna, reaching a length of 200 mm. Four
species of hirudiniform leeches are thus found in Maine and vicinity and
their complete taxonomy is given in Table I. Although this paper
reports Haemopis marmorata from Maine for the first time, its occur-
rence in the state is not unexpected. It is a fairly common species and
has been reported from nearby areas (Meyer, 1937; Smith 1986).
There are two other local leech species in the Suborder
Erpobdelliformes, Erpobdella punctata (Leidy 1870) and Nephelopsis
obscura Verrill 1872, which can be confused with hirudiniforms. Both
species are fairly large predators (reaching 100 mm) but have generally
narrower bodies and contain fewer eyes than hirudiniform leeches.
Additionally, the eyes of erpobdelliform leeches are not arranged in an
arc-like fashion (see Klemm, 1985, 1991a, b). The key treats only those
hirudiniform leeches found in Maine. For more general keys that in-
clude many additional species not found in the region see Klemm (1985,
1991a, b), Sawyer (1972, 1986), and Davies (1991).
Key to the hirudiniform species of Maine
la. Ventral surface with copulatory glands (Figs. 3, 4) in addition to
reproductive pores 2
lb Ventral surface without copulatory glands 3
2a Copulatory gland with four small pores, reproductive openings
separated by at least four annuli (Fig. 3) Macrobdella decora
2b Copulatory gland with 24 minute pores, male and female reproduc-
tive openings separated by less than three annuli (Fig. 4) Macrobdella sestertia
3a Pharynx with three distinct jaws, each with a row of teeth (Figs. 2,
5) (see note below) Haemopis marmorata
3b Pharynx with indistinct jaws and without teeth (Fig. 6) Haemopis grandis
Table I. Classification of the hirudiniform leeches of Maine [after Sawyer's
Haemopis marmorata (Say 1824)
Haemopis grandis (Verril11874)
Macrobdella decora (Say 1824)
Macrobdella sestertia Whitman 1886
1997 D. G. Smith and S. Han1on 235
Note: when preparing specimens for study, mount with ventral surface
up and using a sharp blade make two deep incisions, each beginning at
the mouth and extending just inside of the lateral margin (Figs. 5,6).
Firmly pull back ventral body wall and pin out. If present, the two
ventrolateral jaws with teeth will become visible (Fig. 5).
Figure 3. Ventral surface of M. decora showing external reproductive area.
Scale equals 10 mm and applies. Figure 4. Ventral surface of M. sestertia
showing external reproductive area. Scale equals 10 mm.
236 Northeastern Naturalist
We thank T. R. Whit tier for information regarding EMAP operations and
Karsten Hartel for facilitating the transfer of specimens.
LITERA TURE CITED
Davies, R. W. 1991. Annelida: leeches, polychaetes, and acanthobdellids. In J.
H. Thorp and A. P. Covich, Eds. Ecology and Classification of North
American Freshwater Invertebrates. Academic Press, San Diego, CA. pp.
Klemm, D. J. 1985. A Guide to the Freshwater Annelida (Polychaeta, Naidid
and Tubificid 01igochaeta, and Hirudinea) of North America. Kendall/Hunt,
Dubuque, IA. 198 pp.
Klemm, D. J. 1991a. Taxonomy and pollution ecology of the Great Lakes region
leeches (Annelida: Hirudinea). Mich. Acad. 24: 37-103.
Klemm, D. J. 1991b. Hirudinea. In Peckarsky, B. L., et al., eds. Freshwater
Macroinvertebrates of Northeastern North America. Cornell University
Press, Ithaca, NY. pp. 398-415.
Meyer, M. C. 1937. Notes on some leeches from Ontario and Quebec. Can.
Field-Nat. 51: 117-119.
Rupp, R. S., and M. C. Meyer. 1954. Mortality among brook trout, Salvelinus
jontinalis, resulting from attacks of freshwater leeches. Copeia 1954: 294-
Sawyer, R. T. 1972. North American freshwater leeches, exclusive of the
Piscicolidae, with a key to all species. Ill. Bioi. Monogr. 46: 1-154.
Sawyer, R. T. 1986. Leech Biology and Behaviour. Volume II. Feeding Biol-
ogy, Ecology, and Systematics. Oxford University Press, Oxford, England.
Smith, D. G. 1977. The rediscovery of Macrobdella sestertia Whitman
(Hirudinea: Hirudinidae). J. Parasitol. 63: 759-760.
Smith, D. G. 1986. Notes on the leeches (Hirudinea) of the Connecticut Lakes
region of northern New Hampshire. Proc. Helminthol. Soc. Wash. 53: 294-
Whitman, C. 0. 1886. The leeches of Japan. Q. Microsc. Sci. 26: 378-382.