7723

• UCREFRP Catalog Number: 7723
• Author: Snyder, D. E. and R. T. Muth
• Title: Editor
• USFW Year: Series
• USFW - Doc Type: 1990
• Copyright Material: NO

axis) or with more extensive coil
development (gut phase 5) ........... 9

6 (5). Pigmentation on ventro-lateral surfaces of
peritoneum
a. absent, obstructed from view by muscle,
sparse, or patchy (Figs. 20, 34, 90) ..... 7
b. uniformly dark (Fig. 76) . . C. platyrhynchus

7 (S,6). Mouth
a. terminal (above bottom-of-eye level)

. . . . . . . . . . . . . . . . . . . . . X. texanus
b. low terminal (at or below bottom-of-eye
level) to slightly subterminal (mouth,
including upper lip, not the most anter-
ior portion of snout) (F'igS. 20, 24, 90) . . . 8
c. distinctly subterminal (mouth notably
posterior to most anterior portion of
snout) (Fig. 63) ......... C. commersoni

8 (7). Scales
a. not apparent (FJgS. 20, 34, 90) ...... 100
b. present but lateral series incomplete or
uncountable ................ C.ardens

9 (5). Pigmentation on ventro-Iateral surfaces of
peritoneum
a. absent, obstructed from view by muscle,
sparse, or patchy (Fig. 34) . C. commersoni
b. uniformly dark (Figs. 48, 76) . . . . . . . . . 21

10 (1). Gut (Fig. 5) with
a. full loop (s-shape to near anterior end of
visceral cavity) but with neither limb of
loop completely across over ventral mid-
line (gut phase 3) . . . . . . . . . . . . . . . . . 11
b. at least one limb of loop fully across
ventral midline but not yet with both
limbs across fully to opposite side (gut

phase 4) ....................... 13
c. both limbs of loop across midline fully
to opposite side (four segments of gut
crossing nearly perpendicular to body
axis) or with more extensive coil devel-
opment (gut phase 5) . . . . . . . . . . . . .. 17

11 (10). Mouth
a. terminal (above bottom-of-eye level)

. .. .. .. .. .. .. .. . .. .. . X. texanus
b. low terminal (at or below bottom-of-eye
level) to slightly subterminal (mouth,
including upper lip, not the most anter-
ior portion of snout) (Figs. 20, 90) 12

12 (11). Scales
a. not apparent (F'igS. 20, 90) ......... 111
b. present but lateral series incomplete or
uncountable . . . . . . . . . . . . . . . . C. ardens

13 (10). Pigmentation on ventro-Iateral surfaces
of peritoneum
a. absent, obstructed from view by muscle,
sparse, or patchy (Figs. 20, 34) ....... 14
b. uniformly dark (Fig. 76) . . C. platyrhynchus

14 (13). Pigmentation on ventral surface of
peritoneum
a. absent (F'igS. 20, 34) . . . . . . . . . . . . . ., 15
b. sparse or patchy (Fig. 63) . . C. commersoni

15 (14). Mouth
a. terminal (above bottom-of-eye level)

. .. . .. .. .. . .. . .. . .. . X. texanus
b. low terminal (at or below bottom-of-eye
level) to slightly subterminal (mouth,
including upper lip, not the most anter-
ior portion of snout) (Figs. 20, 34) .... 16
c. distinctly subterminal (mouth notably
posterior to most anterior portion of
snout) (Fig. 63) ......... C. commersoni

16 (15). Scales
a. not apparent (Figs. 20, 34, 90) ...... 100
b. present but lateral series incomplete or
uncountable . . . . . . . . . . . . . . . . . . .. 104

17 (10). Pigmentation on ventro-Iateral surfaces
of peritoneum
a. absent, obstructed from view by muscle,
sparse, or patchy (Figs. 34, 90) ....... 18
b. uniformly dark (Figs. 48, 76) ........ 21

18 (17). Pigmentation on ventral surface of
peritoneum
a. absent (Figs. 34, 90) . . . . . . . . . . . . . .. 19
b. sparse or patchy (Figs. 63) . C. commers01li

19 (18). Mouth
a. terminal (above bottom-of-eye level)

.. .. .. .. . .. .. .. . .. .. X. texanus
b. low terminal (at or below bottom-of-eye
level) to slightly subterminal (mouth,
including upper lip, not the most anter-
ior portion of snout) (Figs. 34,90) .... 20
c. distinctly subterminal (mouth notably
posterior to most anterior portion of
snout) (Fig. 63) ......... C. commersoni

20 (19). Scales
a. not apparent (Figs. 34, 90) ......... 108
b. present but lateral series incomplete or
uncountable . . . . . . . . . . . .. C. commersoni

21 (9,17). Pigmentation on ventral surface of
peritoneum
a. sparse or patchy (Figs. 48, 76) ....... 22
b. uniformly light or dark (Fig. 49)
. . . . . . . . . . . . . . . . . . C. discobolus

22 (21). Mouth
a. terminal (above bottom-of-eye level) or
low terminal (at or below bottom-of-eye
level) to slightly subterminal (mouth,
including upper lip, not the most anter-
ior portion of snout) (FIg. 75)
. . . . . . . . . . . . . . . . C. platyrhynchus
b. distinctly subterminal (mouth notably
posterior to most anterior portion of
snout) (FigS. 48, 76) . . . . . . . C. discobolus

83