Sorex fontinalis

Maryland Shrew
(*Sorex fontinalis*)
Maryland Shrew (Sorex fontinalis)
Range
Taxonomic classification
Order:	Eulipotyphla
Suborder:	Erinaceota
Family:	Soricidae
Subfamily:	Soricinae
Tribe:	Soricini
Genus:	Sorex
Subgenus:	Otisorex
Species group:	Sorex cinereus group
Binomial details
	Sorex fontinalis Hollister, 1911
Other resources
	Full taxonomic details at MDD

The Maryland Shrew (Sorex fontinalis) is a small brown shrew with a complex taxonomic history. It is restricted to a small area in east-central United States. It was originally elevated to full specific rank as Sorex fontinalis by Hollister (1911). The American Society of Mammalogists Mammal Diversity Database (v2.3, released September 1, 2025) tentatively includes fontinalis in Sorex cinereus, stating that "further studies using integrative taxonomic methods are needed". However, Diersing (2025) conducted a detailed morphological analysis on the dentition and skull of long-tailed shrews from east-central United States previously referred to Sorex fontinalis Hollister, 1911, and S. cinereus Kerr, 1792 and found that "all morphological and distributional evidence presented is in agreement with those molecular studies that regard S. fontinalis as a distinct species, separate from S. cinereus."

Description

Sorex fontinalis resembles a smaller Masked Shrew (Sorex cinereus).

From Gatens (1996): "The type specimen of S. c. fontinalis measures 90 mm total length and 31 mm tail vertebrae, well within the range of S. c. cinereus (Jackson, 1928). Jackson listed the total and tail lengths for S. c. fontinalis as 86 to 98 mm and 33 to 37 mm respectively; pelage is darker brown both dorsally and ventrally, and the tail is distinctly bicolored."

External measurements

Length measurements are in millimeters (mm) and weight measurements are in grams (g), unless stated otherwise. If available, the sample size (n=) is provided. If a range is not provided and n= is not given, then the listed measurement represents an average.

Part of range	Reference	Total length	Tail length	Hindfoot length	Mass
Delaware, Maryland, Virginia	Kirkland Jr. (1977)	85.36 (n=11)	32.55 (n=11)	11.27 (n=11)
not reported	Whitaker Jr. & Hamilton Jr. (1998)	78–97	27–39	10–13	2.3–4.5
Pennsylvania	Kirkland Jr. (1977)	85.63 (n=23)	33.33 (n=23)	11.09 (n=23)

Skull

Sorex fontinalis skull characters

units in mm

Skull

Condylobasal length:	14.63–15.85 (Kirkland & Levengood, 1987); 14.6–15.2 (Junge & Hoffman, 1981)
Postmandibular canal:	Absent
Shape:	Skull relatively flat

Dental

Upper unicuspids:	5
Unicuspid notes:	U3≥U4
Tines present:	Yes
Tine size:	Small
Tine position:	Just below the upper limit of pigment on upper incisors
Shape upper incisors:	Diverging

MSB:Mamm:53184. Dorsal view of the skull of Sorex fontinalis.
MSB:Mamm:53184. Ventral view of the skull of Sorex fontinalis.
MSB:Mamm:53184. Lateral view of the skull of Sorex fontinalis. Long scale bar is 1 cm.
Holotype: USNM 85439. Sorex fontinalis. Old adult female. Cold Springs Swamp, near Beltsville, Prince Georges County, Maryland. Collected 6 November 1898. Lateral view of the skull. The skull is damaged.
MSB:Mamm:53184. Unicuspids of Sorex fontinalis. Scale bar is 1 mm.
MSB:Mamm:53184. Upper incisors of Sorex fontinalis. Scale bar is 1 mm.

Taxonomic notes

From Kirkland (1977): "The Maryland shrew, Sorex cinereus fontinalis, was originally accorded full specific rank as Sorex fontinalis by Hollister [1911] based on a type specimen from Cold Spring Swamp, near Beltsville, Prince Georges Co., Maryland. Jackson [1928] retained S. fontinalis as a species since, at that time, no specimens were available for study from the geographic region between the known ranges of S. fontinalis in Maryland and S.c. cinereus in the mountains of Pennsylvania. Jackson acknowledged the possibility that specimens from this intervening region might exhibit characters intermediate between S. fontinalis and S.c. cinereus. In 1937, Poole [1937] described a series of recently collected Sorex from southeastern Pennsylvania as being intermediate in character between typical S. fontinalis from Maryland and S.c. cinereus from the mountains of Pennsylvania. On the basis of these specimens, he relegated S. fontinalis to subspecific status; however, he presented no data from either skins or skulls to substantiate his taxonomic revision. During the ensuing 40 years, mammalogists who have examined Sorex cinereus from the southeastern quadrant of Pennsylvania have noted the difficulty in ascertaining the correct subspecific identity of specimens from this region [Gifford & Whitebread, 1951].

From Gatens (1996): "Based on an extensive analysis re-evaluating its taxonomic status, Kirkland (1977) supported Poole’s original designation, but declined to offer a formal name change pending further study. In the most comprehensive study to date, van Zyll de Jong and Kirkland (1989) argued against specific status for S. c. fontinalis."

From Woodman (2018): "Subgenus Otisorex; Southern clade of the Sorex cinereus group (Hope et al., 2012). Apparently, the taxonomic status of S. fontinalis is still questionable (e.g., Hutterer, 2005) despite the fact that Kirkland (1977) and Kirkland and Levengood (1987) showed clear size differences between S. cinereus and S. fontinalis in Pennsylvania and Kirkland (1977) reported the two taxa in sympatry in Lancaster and York Counties, Pennsylvania."

From Diersing (2025): "Using univariate and multivariate statistics, a detailed morphological analysis was conducted on the dentition and skull of long-tailed shrews from east-central United States previously referred to Sorex fontinalis Hollister, 1911, and S. cinereus Kerr, 1792. Based on the examination of 243 shrews, using 25 measurements, these 2 cryptic taxa have parapatric distributions near the border of the Appalachian Mountains and Ridge and Valley physiographic regions in eastern West Virginia, western Maryland, and southwestern Pennsylvania then eastward through central Pennsylvania to the Delaware River, there southward along the Delaware river and bay. Using univariate statistics, about 84% of individuals can be distinguished from each other. Using discriminant function analysis about 98% of individuals are separable with an average jackknife classification error rate of 11%. Both taxa were found within 3 to 54 km of each other at multiple localities without any evidence of morphological intergradation. However, at 1 locality, 5 of 7 specimens collected on the line of parapatry classified as unknowns and appear to have some morphological traits of both species. All morphological and distributional evidence presented is in agreement with those molecular studies that regard S. fontinalis as a distinct species, separate from S. cinereus."

Details regarding the complex taxonomic history of Sorex fontinalis are outlined in Diersing (2025).

Similar species

Comparison with Sorex cinereus

From Gatens (1996): "The skull of S. c. cinereus has a relatively high and rounded braincase rising above the relatively long and narrow rostrum. The teeth of S. c. cinereus are narrow and the third unicuspid is usually larger than the fourth (Hall, 1981). The condylobasal length usually measures between 15.0 and 16.5 mm though extreme measurements of 13.8 to 17.0 mm have been recorded from the periphery of its range (French, 1980; Junge and Hoffmann, 1981). The skull of S. c. fontinalis is smaller than that of S. c. cinereus, with a shorter broader rostrum, relatively flatter braincase and shorter unicuspid toothrow. Condylobasal length ranges from 14.6 to 15.2 mm (Junge and Hoffmann, 1981). Sorex l. longirostris generally measures 13.8 to 15.6 mm in condylobasal length. It also has a flatter and broader braincase than S. cinereus and a shorter rostrum with a more crowded unicuspid toothrow. The third unicuspid tooth is smaller than or subequal to the fourth unicuspid (Junge and Hoffmann, 1981)."

From Diersing (2025): "No single skull character or measurement is known that will distinguish all individuals of S. fontinalis from S. cinereus. The vast majority of specimens can be identified using the biplot in Fig. 1 [see Diersing, 2025] and the skull measurements in Table 1 [see Diersing, 2025]. In general, the best measurements for recognition of S. fontinalis are unicuspid toothrow length, toothrow length, braincase breadth, skull length, and post-palatal length. All of these measurements are smallest in S. fontinalis. In the west and central regions M2 to M2 breadth, which is largest in S. fontinalis, is helpful in recognition."

Lateral view of the skull of the Maryland Shrew (Sorex fontinalis).
Lateral view of the skull of the Masked Shrew (Sorex cinereus).
Upper incisors of the Maryland Shrew (Sorex fontinalis).
Upper incisors of the Masked Shrew (Sorex cinereus).
Unicuspids of the Maryland Shrew (Sorex fontinalis).
Unicuspids of the Masked Shrew (Sorex cinereus).

References

Diersing VE. 2025. Status of the Maryland Shrew, Sorex fontinalis Hollister, 1911, based on new morphological and distributional evidence from Pennsylvania and adjacent states. Journal of Mammalogy 106(3): 798-813. https://doi.org/10.1093/jmammal/gyaf015

French TW. 1980. Natural history of the southeastern shrew, Sorex longirostris Bachman. American Midland Naturalist: 13-31.

Gatens LJ. 1996. Geographic variation of Sorex cinereus in West Virginia. Master's of Science Thesis. Marshall University.

Gifford CL, Whitebread R. 1951. Mammal Survey of South Central Pennsylvania. Pennsylvania Game Commission, Harrisburg 75 pp.

Hall ER. 1981. The mammals of North America. Second edition. John Wiley & Sons, New York.

Hollister N. 1911. Remarks on the long-tailed shrews of the eastern United States, with description of a new subspecies. Proc. U.S. N Mus. 40: 377-381.

Hope AG, Speer KA, Demboski JR, Talbot SL, Cook JA. 2012. A climate for speciation: rapid spatial diversification within the Sorex cinereus complex of shrews. Molecular Phylogenetics and Evolution 64(3): 671-684.

Hutterer R. 2005. Order Soricomorpha. Pp. 220–311 in Mammal species of the world: a taxonomic and geographic reference, 3rd edition (D. E. Wilson and D. M. Reeder, eds.). Johns Hopkins University Press, Baltimore, Maryland.

Jackson HHT. 1928. Taxonomic review of the North American long-tailed shrews (genera Sorex and Microsorex). North America Fauna 51: 1-238.

Junge JA, Hoffman RS. 1981. An annotated key to the long-tailed shrews (genus Sorex) of the United States and Canada, with notes on Middle American Sorex. Occas. Papers Mus. Nat. Hist., Univ. Kansas 94:1-48.

Kirkland Jr GL. 1977. A re-examination of the subspecific status of the Maryland shrew, Sorex cinereus fontinalis Hollister. In Proceedings of the Pennsylvania Academy of Science (pp. 43-46). Pennsylvania Academy of Science.

Kirkland GL, Levengood JM. 1987. First record of the Maryland shrew (Sorex fontinalis) from West Virginia. In Proceedings of the Pennsylvania Academy of Science (pp. 35-37). Pennsylvania Academy of Science.

Poole EL. 1937. Pennsylvania records of Sorex cinereus fontinalis. Journal of Mammalogy 18: 96.

van Zyll de Jong CG, Kirkland Jr GL. 1989. A morphometric analysis of the Sorex cinereus group in central and eastern North America. Journal of Mammalogy 70(1): 110-122.

Woodman N. 2018. American Recent Eulipotyphla: Nesophontids, Solenodons, Moles, and Shrews in the New World. Smithsonian Institution Scholarly Press. Book. https://doi.org/10.5479/si.1943-6696.650