Key To Cambarellus

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KEY TO THE SPECIES OF THE GENUS CAMBARELLUS
(Based on the First-Form Male)

Species NOT appearing in this Key:

 Species  Range
Cambarellus blacki FL: Escambia Co.
Cambarellus lesliei MS: Baldwin, Mobile, & Washington Counties and
AL: George Co.
Cambarellus texanus TX: East of Lavaca R. and Bay to the Brazos River drainage.
Cambarellus prolixus Lago de Chapala, Jalisco, Mexico
Cambarellus chihuahuae Chihuahua, Mexico

NOTE:  In using this key, the first pleopod must be viewed mesially.  For comparative purposes, all of the illustrations of this appendage are made of the left member of the pair.


1.    Mesial process of first pleopod without longitudinal groove along mesial surface of apical 1/3
       (Fig. 15):..........................................................................................................................................................   2
  • Mesial process of first pleopod with longitudinal groove along mesial surface of apical 1/3
    (Fig. 16):.......................................................................................................................................................   7

 

 

Fig. 15.  Mesial view of left first pleopods.  a, Cambarellus shufeldtii
b, C. diminutus;  c, C. schmitti;  d, C. ninae;  e, C. puer;  f, C. alvarezi
(after Villalobos, 1955)

2 (1). Terminal elements of first pleopod almost straight and directed distally (Fig 15a):
           ......................................................................................................  Cambarellus shufeldtii (Faxon, 1884).

        (Lentic and sluggish lotic habitats in the Mississippi drainage system of southern Illinois,
         Tennessee, Arkansas and Louisiana; in the Red River system in Louisiana and Texas; 
         and in the Pascagoula and Pearl River systems in Mississippi.  Introduced into Rapides,
         St. Bernard and St. Tammany parishes, Louisiana.  Literature:  Black, 1965; Hobbs and
         Marchand, 1943; Penn, 1959
).

  • Central projection of first pleopod always curved and other terminal elements never directed
    distally (Fig. 15b-f): ....................................................................................................................................  3

3(2).  Caudal process of first pleopod broadly triangular and in lateral aspect obscuring mesial
           process (Fig. 15b): ...................................................................  Cambarellus diminutus Hobbs, 1945

        (Lentic and sluggish lotic habitats in Mobile County, Alabama, and George and Jackson
           counties, Mississippi.  Literature:  Hobbs, 1945b; Black, 1965
).

  • Caudal process of first pleopod digitiform or subsetiform and in lateral aspect never obscuring
    mesial process (Fig. 15c-f): ......................................................................................................................  4

4(3).  Mesial process of first pleopod broadly triangular, its apex curved distolaterally (Fig. 15c): .............
          ..........................................................................................................  Cambarellus schmitti Hobbs, 1942 

        (Springs and streams from Mobile County, Alabama, eastward to the Suwannee River drainage
          in Florida.  Literature:  Hobbs, 1942b
).

  • Mesial process comparatively slender and directed subcaudally (Fig. 15d-f): .....................................  5
Fig. 16.  Mesial view of left first pleopods.  a, Cambarellus occidentalis;
 b, C. areolatus;  c, C. chapalanus;  d, C. patzcuarensis;  e, C. zempoalensis;
 f, C. montezumae.

5(4).   Central projection of first pleopod directed caudally and extending much beyond other terminal
           elements (Fig. 15d): ...........................................................................  Cambarellus ninae Hobbs, 1950

        (Lentic habitats in Aransas County, Texas.  Literature: Hobbs, 1950).

  • Central projection of first pleopod directed caudodistally and not extending caudally so far as
    other terminal elements (Fig. 15e,f)  ..........................................................................................................  6

6(5).  Mesial process of first pleopod subsetiform (Fig. 15f) ...........  Cambarellus alvarezi Villalobos, 1952

       (Lentic habitat at Potosí, Nuevo León, 23 km. northwest of Galena, México; known only
         form the type-locality.  Literature: Villalovos, 1955)

  • Mesial process of first pleopod robust but subacute (Fig. 15e; see also Fig 5c):..............................
    .................................................................................................................  Cambarellus puer  Hobbs, 1945

        (Lentic and sluggish lotic habitats from Brazos and Matagorda counties, Texas, to western
         Tennessee, Holmes County, Mississippi, and Ascension Parish, Louisiana.  Literature:
         Penn and Hobbs, 1958; Black, 1965),


7(1).  Central projection of first pleopod constituting at least 1/5 total length of appendage (Fig. 16a,b)
           ........................................................................................................................................................................  8

  • Central projection of first pleopod constituting at less than 1/5 total length of appendage
    (Fig. 16c-f).....................................................................................................................................................  9

8(7).  Areola at least 3.5 times longer than broad (Fig. 17a; see also Fig. 16a):..........................................
          ...............................................................................................  Cambarellus occidentalis  (Faxon, 1898)

        (Lentic habitats in Michoacán and Sinaloa, México.  Literature:  Faxon, 1898; Villalobos, 1955).

  • Areola less than 3.5 times longer than broad.  (Fig.  17b; see also Fig. 16b)....................................
    ...................................................................................................  Cambarellus areolatus (Faxon, 1885)

        (Lotic habitats in Coahuila, México.  Literature: Faxon, 1898; Villalobos, 1955).

Fig. 17.  Dorsal view of carapaces.  a, Cambarellus occidentalis
b, C. areolatus;  c, C. chapalanus;  e, C. patzcuarensis.

9(7).  Length of acumen of rostrum as great or greater than distance between tips of marginal
          spines (Fig. 17c,d)....................................................................................................................................  10

  • Length of acumen of rostrum less than distance between tips of marginal spines (Fig.
    17c,d
    ).........................................................................................................................................................  11

10(9).  Acumen decidedly longer than distance between tips of marginal spines of rostrum; cephalothorax
             slender and gently tapering in width anteriorly (Fig. 17c; see also Fig. 16c):  ...................................
             ...........................................................................................  Cambarellus chapalanus  (Faxon, 1898)

        (Lentic habitats in Jalisco and Michoacán, México.  Literature:  Faxon, 1898; Villalobos, 1955)

  • Acumen subequal to or only slightly longer than distance between marginal spines of rostrum;
    cephalothorax somewhat robust and rather abruptly tapering in width anteriorly (Fig. 17d; see
    also Fig. 16d):  ............................................................  Cambarellus patzcuarensis  Villalobos, 1943

        (Lago de Patzcuaro, Michoacán, México.  Literature:  Villalobos, 1955)

Fig. 18.  a,b, Dorsal view of carapaces;  c,d, Dorsal view of chelae.
 a, Cambarellus zempoalensis;  b, C. montezumae;  c, C. zempoalensis;
 d, C. montezumae.

11(9).  Lateral margin of chela strongly convex (Fig. 18c; see also Figs. 16e, 18a):  .................................
            ....................................................................................  Cambarellus zempoalensis  Villalobos, 1943

        (Lagunas de Zempoala, Morelos, México.  Literature:  Villalobos, 1955).

  • Lateral margin of chela not markedly convex (Fig. 18d; see also Figs. 16f, 18b):  ............................
    .......................................................................................  Cambarellus montezumae (Saussure, 1858)

        (Sluggish streams and lentic situations in the Valley of México and Pacific slope.  The
          subspecies
C. m. dugesii (Faxon, 1898) and C. m. lermensis Villalobos, 1943, cannot
          be separated by me from the typical form of the species.  Literature:  Villalobos, 1955)


Last Updated:  10 September 2004