KEY TO THE SPECIES OF THE SUBGENUS VILLALOBOSUS

• Mesial process of first pleopod extending little, if any, farther distally than other terminal elements
  (Fig. 57d-i):..................................................................................................................................................  4

2(1).   Mesial process of first pleopod comparatively small and exceeding other terminal elements by
            no more than 1/2 their length (Fig. 57a):.................  Procambarus (V.) hoffmanni  (Villalobos, 1944).

       (Tributaries of the Río Tecolutla and Río Nautla in Puebla and Veracruz, México.
         Literature:  Villalobos, 1955).

• Mesial process of first pleopod very large and exceeding other terminal elements by at least
  2/3 their lengh (Fig. 57b, c):.......................................................................................................................  3

3(2).   Mesial process of first pleopod somewhat flattened and sinuous (at least caudal margin
           sinuous) (Fig. 57b);  areola with no more than 2 punctations across narrowest part:........
           .........................................................................  Procambarus (V.) tlapacoyanensis (Villalobos, 1947).

       (Tributaries of the Río Nautla in the vicinity of Tlapacoyan, Veracruz, México.
         Literature:  Villalobos, 1947).

• Mesial process of first pleopod conical and nearly straight (Fig. 57c); areola with more than
  2 punctations across narrowest part:...............  Procambarus (V.) teziutlanensis  (Villalobos, 1947).

       (Headwater tributaries of the Río Nautla in Puebla and Veracruz, México.
         Literature:  Villalobos, 1955).

4(1).   First pleopod with 2 spiniform processes (mesial and cephalic) subequal in length, both
           projecting distally beyond other terminal elements (Fig. 57d; see also Fig. 6c):.................................
.........................................................................................................  Procambarus (V.) riojai  (Villalobos, 1944).

       (Headwater tributaries of the Río Cazones and Río Tecolutla in Hidalgo and Puebla,
        México.  Literature:  Villalobos, 1955).

• First pleopod with only 1 conspicuous spiniform or subspiniform process (mesial), or, if
  cephalic process somewhat spiniform, never extending distally beyond other terminal
  elements (Fig. 57e-i):................................................................................................................................  5

5(4).   Cephalic process of first pleopod well developed, slender, never platelike, situated cephalomesially,
            and extending distally to or slightly beyond level of tip of mesial process (Fig.  57e):..........................
            .......................................................................................  Procambarus (V.) erichsoni  Villalobos, 1950.

       (Tributaries of the Rio Pantepec (to Rio Tuxpan) in the vicinity of Tenango de Doria, Hidalgo,
         Mexico.  Literature:  Villalobos, 1955).

• Cephalic process of first pleopod either forming curved crestlike plate, or very much reduced; never extending distallt to level of tip of mesial process (fig. 57f-i):................................................................  6

6(5).   Curved crestlike plate on cephalodistal surface of first pleopod flared from base (Fig. 57f):...........
           ................................................................................  Procambarus (V.) zihuateutlensis  Villalobos, 1950.

       (Headwater tributaries of the Río Tecolutla in the vicinity of Zihuateutla, Puebla, México.
        Literature: Villalobos, 1955).

• Curved crestlike plate on cephalodistal surface of pleopod not flared from base, extending
  distally (Fig. 57g-i):...................................................................................................................................  7

Fig. 57.  a-g, i, Lateral view of distal portion of left first pleopods;  h, Mesial view of same.  a, Procambarus hoffmanni;  b, P. tlapacoyanensis;  c, P. teziutlanensis;  d, P. riojai;  e, P. erichsoni;  f, P. zihuateutlensis;  g,h, P. contrerasi;  i, P. hortonhobbsi.  (cp, cephalic process;  m, mesial process).

7(6).   Central projection of first pleopod masked in lateral aspect by crestlike plate; cephalic process
           small and situated caudomesial to restlike plate (Fig. 57g, h):.........................................................
           ............................................................................................  Procambarus (V.) contrerasi (Creaser, 1931).

       (Tributaries of the Río Cazones and the Río Tecolutla in the vicinity of Zihuateutla and
        Agua Fría, Puebla, México.  Literature:  Villalobos, 1955).

• Central projection of first pleopod clearly evident in lateral aspect; cephalic process forming
  crestlike plate (Fig. 57i):.........................................  Procambarus (V.) hortonhobbsi  Villalobos, 1950.

       (Stream at El Coyular, 7km.  northeast of La Unión, Municipio de Zihuateutla, Puebla, México.
         Literature:  Villalobos, 1955).

END OF VILLALOBOSUS

Last Updated:  10 September 2004