32
Distribution. S. linderi is known from Texas, USA,
and from the Mexican states of Coahuila, Nuevo Leon,
and Tamaulipac (Moore, 1966; Belk, 1975; MaedaMartinez, 1991).
Streptocephalus mackini Moore, 1966
(Fig. 10 A-E)
Streptocephalus mackini Moore, 1966; Brtek,
1974; Belk, 1975; Spicer, 1985; Pennak, 1989; MaedaMartinez, 1991.
Type material. Holotype USNM 113039, paratypes
USNM 113040, and LU 1077, Loyola University
Museum, New Orleans, Louisiana, USA.
Type locality. Federal Highway 75, 15 mi S Arteaga,
Coahuila, Mexico.
Material examined. ENEP91.04. La Herradura, Soianiquilpan, Estado de Mexico, Mexico 10 d' d' 13.9
(12.9-15.1) mm; HMPS VII/a-4473 Arroyo Hondo,
Tepezahi, Aguascalientes, Mexico 4 d' d' 14.9 (13.716.4) mm; HMPS VII/a-4474 Mesa Grande, Calvillo,
Aguascalientes, Mexico 3 d' d' 17.5 (16.8-17.9) mm,
5 Q Q 17.7 (16.8-18.7) mm; UG 094 Culberson
County, Texas, USA 7 d' d' 15.7 (14.4-17.0) mm,
4 Q Q 15.2 (14.0-16.0) mm; UJED 180 La Posta,
Culiacan, Sinaloa, Mexico 12 d' d' 26.5 (24.8-28.7)
mm, 15 Q Q 28.3 (28.0-29.5) mm; UIED 19288 km
E1 Sueco Buenaventura, Chihuahua 10 d' 28.9 (25.732.2) mm, 8 Q Q 33.3 (31.0-35.0) mm; UIED 243
El Refugio bridge 70 km E Torreon, Coahuila, Mexico
12 d' d' 12.3 (11.1-14.0) mm; UJED 290 pond at Universidad Autonoma de Aguascalientes, Mexico 12 d'
d' 13.4 (12.0-14.4)mm, 10 QQ 12.9 (12.4-14.0)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 triangleshaped, apex with subapical swollen part, finishing
subacuminate; lateral lamella with acute angle between
distal part of thumb and spur; inner lamella medianventrally produced forming a cavity; distal part of thumb
inerm, geniculate, with ventral elbow, apex acuminate;
finger bigeniculate, two teeth on inner dorsal side of
proximal part; distal tooth broad at base, its anterior margin anterodorsally prolonged into an acuminate
structure; proximal tooth shorter, subacuminate and
anteriorly oblique, its apical part projecting beyond
posterior margin of distal tooth; finger, at first geniculation, with broad dorsal lamella, narrow at second
geniculation; apex of finger acuminate, with subapical
swollen part armed with lateral, spiniform, anteroventrally directed structure; frontal appendage simple,
short, usually bilobed at tip; genitalia without linguiform outgrowths; cercopods separate, setose along
inner and lateral borders; anus terminal.
Female. Ovaries biramous variably extending from
thoracic segments 5-10 to abdominal segments 5-6;
sphaerical cysts ornamented by ribs forming polygonal areas.
Differential diagnosis. As discussed above, the only
character useful to differentiate S. mackini from S.
dorothae, is the lateral, spiniform, anteroventrally
directed structure at the apex of the finger. In fact
no other streptocephalid presents such a structure. S.
moo rei has, however, a digitiform protuberance in ventrolaterally position (Fig. 1 B, C). Nevertheless, S.
moorei and S. antillensis, of the same mackini subgroup, have spiniform structures on the thumb, while
in S. mackini, the thumb is inerm. Apart from differences in shape of the apex of the finger and the spur of
the thumb, the teeth of the finger of S. mackini resemble
those of S. texanus. However, in S. mackini species, the
posterior border of the distal tooth is typically shorter
than the proximal tooth (Fig. 10 C), while in S. texanus,
the same border typically is of about the same size as
the proximal tooth (Fig. 13 C). Beside the differences
mentioned above, S. mackini is distinguished from the
other American forms of the torvicornis subgroup, by
the shape of the proximal tooth of the finger, which is
much smaller in S. guzmani and S. mattoxi (Figs 5 C,
6 C) than in S. mackini (Fig. 10 C).
Distribution. S. mackini is the most common phyllopod
in Mexico, recorded from Aguascalientes, Coahuila,
Chihuahua, Distrito Federal, Durango, Estado de
Mexico, Guanajuato, Hidalgo, Jalisco, Morelos, Nuevo Leon, Puebla, Queretaro, San Luis Potosi, Sinaloa,
Sonora, Tlaxcala, and Zacatecas (Moore, 1966; Belk;
1975; Maeda-Martinez, 1991). In the USA, this species
is known from Arizona, New Mexico, and Texas
(Moore, 1966; Belk, 1975).
Remarks. Given the wide distribution and different
regions from where this species has been recorded, S. mackini presents a case similar to that of S.
sealii. At least in the populations from Sinaloa, some
Distribution. S. linderi is known from Texas, USA,
and from the Mexican states of Coahuila, Nuevo Leon,
and Tamaulipac (Moore, 1966; Belk, 1975; MaedaMartinez, 1991).
Streptocephalus mackini Moore, 1966
(Fig. 10 A-E)
Streptocephalus mackini Moore, 1966; Brtek,
1974; Belk, 1975; Spicer, 1985; Pennak, 1989; MaedaMartinez, 1991.
Type material. Holotype USNM 113039, paratypes
USNM 113040, and LU 1077, Loyola University
Museum, New Orleans, Louisiana, USA.
Type locality. Federal Highway 75, 15 mi S Arteaga,
Coahuila, Mexico.
Material examined. ENEP91.04. La Herradura, Soianiquilpan, Estado de Mexico, Mexico 10 d' d' 13.9
(12.9-15.1) mm; HMPS VII/a-4473 Arroyo Hondo,
Tepezahi, Aguascalientes, Mexico 4 d' d' 14.9 (13.716.4) mm; HMPS VII/a-4474 Mesa Grande, Calvillo,
Aguascalientes, Mexico 3 d' d' 17.5 (16.8-17.9) mm,
5 Q Q 17.7 (16.8-18.7) mm; UG 094 Culberson
County, Texas, USA 7 d' d' 15.7 (14.4-17.0) mm,
4 Q Q 15.2 (14.0-16.0) mm; UJED 180 La Posta,
Culiacan, Sinaloa, Mexico 12 d' d' 26.5 (24.8-28.7)
mm, 15 Q Q 28.3 (28.0-29.5) mm; UIED 19288 km
E1 Sueco Buenaventura, Chihuahua 10 d' 28.9 (25.732.2) mm, 8 Q Q 33.3 (31.0-35.0) mm; UIED 243
El Refugio bridge 70 km E Torreon, Coahuila, Mexico
12 d' d' 12.3 (11.1-14.0) mm; UJED 290 pond at Universidad Autonoma de Aguascalientes, Mexico 12 d'
d' 13.4 (12.0-14.4)mm, 10 QQ 12.9 (12.4-14.0)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 triangleshaped, apex with subapical swollen part, finishing
subacuminate; lateral lamella with acute angle between
distal part of thumb and spur; inner lamella medianventrally produced forming a cavity; distal part of thumb
inerm, geniculate, with ventral elbow, apex acuminate;
finger bigeniculate, two teeth on inner dorsal side of
proximal part; distal tooth broad at base, its anterior margin anterodorsally prolonged into an acuminate
structure; proximal tooth shorter, subacuminate and
anteriorly oblique, its apical part projecting beyond
posterior margin of distal tooth; finger, at first geniculation, with broad dorsal lamella, narrow at second
geniculation; apex of finger acuminate, with subapical
swollen part armed with lateral, spiniform, anteroventrally directed structure; frontal appendage simple,
short, usually bilobed at tip; genitalia without linguiform outgrowths; cercopods separate, setose along
inner and lateral borders; anus terminal.
Female. Ovaries biramous variably extending from
thoracic segments 5-10 to abdominal segments 5-6;
sphaerical cysts ornamented by ribs forming polygonal areas.
Differential diagnosis. As discussed above, the only
character useful to differentiate S. mackini from S.
dorothae, is the lateral, spiniform, anteroventrally
directed structure at the apex of the finger. In fact
no other streptocephalid presents such a structure. S.
moo rei has, however, a digitiform protuberance in ventrolaterally position (Fig. 1 B, C). Nevertheless, S.
moorei and S. antillensis, of the same mackini subgroup, have spiniform structures on the thumb, while
in S. mackini, the thumb is inerm. Apart from differences in shape of the apex of the finger and the spur of
the thumb, the teeth of the finger of S. mackini resemble
those of S. texanus. However, in S. mackini species, the
posterior border of the distal tooth is typically shorter
than the proximal tooth (Fig. 10 C), while in S. texanus,
the same border typically is of about the same size as
the proximal tooth (Fig. 13 C). Beside the differences
mentioned above, S. mackini is distinguished from the
other American forms of the torvicornis subgroup, by
the shape of the proximal tooth of the finger, which is
much smaller in S. guzmani and S. mattoxi (Figs 5 C,
6 C) than in S. mackini (Fig. 10 C).
Distribution. S. mackini is the most common phyllopod
in Mexico, recorded from Aguascalientes, Coahuila,
Chihuahua, Distrito Federal, Durango, Estado de
Mexico, Guanajuato, Hidalgo, Jalisco, Morelos, Nuevo Leon, Puebla, Queretaro, San Luis Potosi, Sinaloa,
Sonora, Tlaxcala, and Zacatecas (Moore, 1966; Belk;
1975; Maeda-Martinez, 1991). In the USA, this species
is known from Arizona, New Mexico, and Texas
(Moore, 1966; Belk, 1975).
Remarks. Given the wide distribution and different
regions from where this species has been recorded, S. mackini presents a case similar to that of S.
sealii. At least in the populations from Sinaloa, some