30
cavity; distal part of thumb inerm, geniculate, forming
a ventral elbow, dorsal side smooth, apex acuminate;
finger bigeniculate, two teeth on inner dorsal side of
proximal part; distal tooth broad at base, with anterior
margin anterodorsally prolongated, forming an acuminate structure; proximal tooth shorter, subacuminate
and anteriorly oblique; its apical part exceeds posterior margin of distal tooth; finger at first geniculation;
apex of finger with subapical, swollen part, finishing
acuminate; frontal appendage simple, short, bilobed
at tip; genitalia without linguiform outgrowths; cercop ods setose along inner and lateral borders; base of
cercopods and telson not confluent; anus terminal.
Female. Ovaries biramous, variably extending
from thoracic segments 4-9 to abdominal segments 56; sphaerical cysts ornamented by ribs forming reduced
polygonal areas.
Differential diagnosis. As already pointed out by
Wiman (1979b) and Belk (1991), the morphology of
the antennae of S. dorothae and S. mackini is virtually
the same. The single character useful to distinguish
them is the lateral spiniform structure of S. mackini
(Fig. 10 E), which is absent in S. dorothae (Fig. 8
F). S. dorothae is easily separated from the remaining
species of the mackini subgroup. While S. antillensis
and S. moo rei present a series of spiniform structures
along the dorsal border of the thumb, S. dorothae has
an inerm thumb. Compared with S. tinderi, S. texanus,
and S. potosinensis n.sp., S. dorothae, beside differences in the shape of the teeth, is distinguished by the
total absence of any structure on the apex of the finger
(Fig. 8 F). For differences with the American forms of
the torvicornis subgroup, see differential diagnosis of
S. guzmani and S. mattoxi.
Distribution. S. dorothae has been recorded from USA,
in Arizona, New Mexico, Oklahoma, Texas, Utha, and
Wyoming (Mackin, 1942; Kohen & Cole, 1964; Maynard & Romney, 1975; Belk, 1983), and recently from
Mexico, in Baja California Sur (Maeda-Martfnez et at.,
1992).
Streptocephalus tinderi Moore, 1966
(Fig. 9 A-E)
Streptocephalus tinderi Moore, 1966; Brtek, 1974;
Belk, 1975; Spicer, 1985; Pennak, 1989; MaedaMartinez, 1991.
Type material. Holotype USNM 113041, paratypes
USNM 113042 and LU 1109, Loyola University
Museum, New Orleans, Louisiana, USA.
Type locality. Pond at US Highway 290, 31 mi W
Ozona, Crockett County, Texas.
Material examined. DB 087 6.4 km SW Sabinas,
Coahuila Mexico 3 cf' cf' 10.3 (10.1-10.5) mm, 3
Cj) Cj) 10.5 (10.0-11.0)mmj HMPS VII/a-2793 Sabinas,
Coahuila, Mexico 5 cf' cf' 10.2 (9.8-10.7) mm, 5 Cj) Cj)
10.1 (9.4-11.3) mm; USNM 12044929 mi W Ozona,
CrocketCounty, Texas, USA 5 cf' cf' 14.3 (13.0-15.0)
mm,5 Cj) Cj) 13.1 (12.0-14.0)mm.
Diagnosis. Male. Peduncle of distal outgrowth of long
type, without pulvinus, with series of c. 8 conical protuberances variable in size, situated on inner side of distal
part; inner dorsal side of base of hand with stout spiniform structure, anteriorly directed, spur blade-shaped,
finishing acuminate; lateral lamella with acute angle
between thumb and spur; inner lamella medioventrally
produced, forming a cavity; distal part of thumb inerm,
geniculate, with ventral elbow, dorsal side smooth,
apex acuminate; finger bigeniculate, two teeth on inner
dorsal side of proximal part; distal tooth broad at base,
with anterior margin anterodorsally prolonged, forming a short acuminate structure; proximal one bigger
and robust, anteromedially oblique and subacuminate;
finger at first geniculation with short dorsal lamella,
narrow at second geniculation; apex of finger with lateroventrally produced lamella, its anteroventral border
variably ornamented by spiniform structures or by a
simple undulated margin; frontal appendage simple,
short, bilobed at tip; genitalia without linguiform outgrowths; cercopods setose along inner and lateral borders; base of cercopods and telson not confluent; anus
terminal. Female. Ovaries biramous, variably extending from thoracic segments 8-10 to abdominal segment
6; cysts sphaerical, ornamented by ribs forming polygonal areas.
Differential diagnosis. S. tinderi, S. potosinensis n. sp.,
and S. texanus, exhibit a number of similarities, such
as the spur of the thumb which is long and acuminate,
without any apparent modification at the apex, and the
presence of a subapical lateral lamella at the apex of
the finger. In S. texanus, however, the distal tooth of
the finger is bigger than the proximal one. Conversely,
in S. tinderi and S. potosinensis the distal tooth is shorter than the proximal one. In fact, this is a distinctive
characteristic of these species from all other members
of torvicornis group. Given the variability in shape of
cavity; distal part of thumb inerm, geniculate, forming
a ventral elbow, dorsal side smooth, apex acuminate;
finger bigeniculate, two teeth on inner dorsal side of
proximal part; distal tooth broad at base, with anterior
margin anterodorsally prolongated, forming an acuminate structure; proximal tooth shorter, subacuminate
and anteriorly oblique; its apical part exceeds posterior margin of distal tooth; finger at first geniculation;
apex of finger with subapical, swollen part, finishing
acuminate; frontal appendage simple, short, bilobed
at tip; genitalia without linguiform outgrowths; cercop ods setose along inner and lateral borders; base of
cercopods and telson not confluent; anus terminal.
Female. Ovaries biramous, variably extending
from thoracic segments 4-9 to abdominal segments 56; sphaerical cysts ornamented by ribs forming reduced
polygonal areas.
Differential diagnosis. As already pointed out by
Wiman (1979b) and Belk (1991), the morphology of
the antennae of S. dorothae and S. mackini is virtually
the same. The single character useful to distinguish
them is the lateral spiniform structure of S. mackini
(Fig. 10 E), which is absent in S. dorothae (Fig. 8
F). S. dorothae is easily separated from the remaining
species of the mackini subgroup. While S. antillensis
and S. moo rei present a series of spiniform structures
along the dorsal border of the thumb, S. dorothae has
an inerm thumb. Compared with S. tinderi, S. texanus,
and S. potosinensis n.sp., S. dorothae, beside differences in the shape of the teeth, is distinguished by the
total absence of any structure on the apex of the finger
(Fig. 8 F). For differences with the American forms of
the torvicornis subgroup, see differential diagnosis of
S. guzmani and S. mattoxi.
Distribution. S. dorothae has been recorded from USA,
in Arizona, New Mexico, Oklahoma, Texas, Utha, and
Wyoming (Mackin, 1942; Kohen & Cole, 1964; Maynard & Romney, 1975; Belk, 1983), and recently from
Mexico, in Baja California Sur (Maeda-Martfnez et at.,
1992).
Streptocephalus tinderi Moore, 1966
(Fig. 9 A-E)
Streptocephalus tinderi Moore, 1966; Brtek, 1974;
Belk, 1975; Spicer, 1985; Pennak, 1989; MaedaMartinez, 1991.
Type material. Holotype USNM 113041, paratypes
USNM 113042 and LU 1109, Loyola University
Museum, New Orleans, Louisiana, USA.
Type locality. Pond at US Highway 290, 31 mi W
Ozona, Crockett County, Texas.
Material examined. DB 087 6.4 km SW Sabinas,
Coahuila Mexico 3 cf' cf' 10.3 (10.1-10.5) mm, 3
Cj) Cj) 10.5 (10.0-11.0)mmj HMPS VII/a-2793 Sabinas,
Coahuila, Mexico 5 cf' cf' 10.2 (9.8-10.7) mm, 5 Cj) Cj)
10.1 (9.4-11.3) mm; USNM 12044929 mi W Ozona,
CrocketCounty, Texas, USA 5 cf' cf' 14.3 (13.0-15.0)
mm,5 Cj) Cj) 13.1 (12.0-14.0)mm.
Diagnosis. Male. Peduncle of distal outgrowth of long
type, without pulvinus, with series of c. 8 conical protuberances variable in size, situated on inner side of distal
part; inner dorsal side of base of hand with stout spiniform structure, anteriorly directed, spur blade-shaped,
finishing acuminate; lateral lamella with acute angle
between thumb and spur; inner lamella medioventrally
produced, forming a cavity; distal part of thumb inerm,
geniculate, with ventral elbow, dorsal side smooth,
apex acuminate; finger bigeniculate, two teeth on inner
dorsal side of proximal part; distal tooth broad at base,
with anterior margin anterodorsally prolonged, forming a short acuminate structure; proximal one bigger
and robust, anteromedially oblique and subacuminate;
finger at first geniculation with short dorsal lamella,
narrow at second geniculation; apex of finger with lateroventrally produced lamella, its anteroventral border
variably ornamented by spiniform structures or by a
simple undulated margin; frontal appendage simple,
short, bilobed at tip; genitalia without linguiform outgrowths; cercopods setose along inner and lateral borders; base of cercopods and telson not confluent; anus
terminal. Female. Ovaries biramous, variably extending from thoracic segments 8-10 to abdominal segment
6; cysts sphaerical, ornamented by ribs forming polygonal areas.
Differential diagnosis. S. tinderi, S. potosinensis n. sp.,
and S. texanus, exhibit a number of similarities, such
as the spur of the thumb which is long and acuminate,
without any apparent modification at the apex, and the
presence of a subapical lateral lamella at the apex of
the finger. In S. texanus, however, the distal tooth of
the finger is bigger than the proximal one. Conversely,
in S. tinderi and S. potosinensis the distal tooth is shorter than the proximal one. In fact, this is a distinctive
characteristic of these species from all other members
of torvicornis group. Given the variability in shape of