The distal outgrowth (Linder, 1941:134)(= medial process (Moore, 1966), antennale Fortsatz (Claus,
1886; Brtek, 1974), S-shaped antennal process (Brendonck & Belk, 1993; Hamer et ai., 1994 a,b)), protruding just above of the apical joint (Figs 1 C-G, 2
A,7 A), consists of two main parts: 1) A peduncle (=
median part or section (Sars, 1898, 1899, 1900, 1905),
articulus secundus (Daday, 1908), articulus medius
(Daday, 1910a,b), second joint (Barnard, 1924), second segment (Mackin, 1942), basale und mittlere Teil
des antennalen Fortsatzes (Brtek, 1974)) (Fig. 2), and
2) a scleroid hand (Sars, 1899, 1900, 1905)(= Zange
(Claus, 1886), chela (Sars, 1898), terminal part or section (Sars, 1899, 1900, 1905), articulus apicalis or
ultimus (Daday, 1908, 191Oa,b), third joint (Barnard,
1924), third segment or scissors (Mackin, 1942), terminale scherenartige Teil des antennalen Fortsatzes
(Brtek, 1974)) (Fig. 2).
In the adult stage, the peduncle is a cylindrical, robust, unigeniculated or bigeniculated structure,
which, depending on the species, is of determinate
length. Comparing this length with the standard length,
basal joint length, and apical joint length, the peduncle
can be defined as short, intermediate, or long (see
Species groups of Streptocephalus). The peduncle,
carried in retracted position except during amplexus,
presents a geniculation near the middle of its extension
(Figs 2 A, 7 A). A second geniculation, at the base of
the hand, rotated more than 50 ° , is present in all long
peduncles (e.g. Fig. 6, E). In only one of the species
groups with an intermediate length peduncle (the cafer
group), the base of the hand exhibits a rotation of c.
50° (e.g. Fig. 6 D). In the other species groups with
intermediate or short peduncles, a rotation of no more
than 40° occurs (e.g. Fig. 6 B). The peduncle can be
ornamented with different and variable processes. A
pad-like protuberance, the pulvinus, is situated on the
laterobasal side of the peduncle (Fig. 7 A, B). Although
the pulvinus is a feature of most species with short and
intermediate peduncles, three species with long peduncles exhibit such a structure.
The basic plan of the hand includes 3 primary
parts: (1) a dorso-Iateral thumb (Barnard, 1929) (=
outer dactylus (Sars, 1899), anterior digitus (Sars,
1898, 1900), digitus exterior or superior (Daday, 1908,
1910a,b), anterior prong (Barnard, 1924), outer part
(Creaser, 1930), Dorsalarm (Brtek, 1974)) (Figs 1 EG, 2, 6); (2) a ventral-inner finger (Barnard, 1929) (=
inner dactylus (Sars, 1899), digitus interior or inferior (Daday, 1908, 191Oa,b), posterior prong (Barnard,
1924), inner part (Creaser, 1930), Ventralarm (Brtek,
213
1974)) (Figs 1 E-G, 2, 6); and (3) a base of the hand
(= palm (Sars, 1898)), at which both former structures
are attached (Fig. 2).
From the basic plan of the hand the next structures
can be derived (Fig. 2, B):
l.lateral lamella (= lamina lateralis (Daday, 1908,
1910a, b)): The blade of the thumb which folds
lateroventrally along the ventral base of the thumb.
2. spur (Mackin, 1942)(= lower lappet (Sars, 1899),
processu (Daday, 1908), lamina lateralis (Daday,
191Oa,b), posterior process (Barnard, 1924) posterior prong (Barnard, 1929), elongate tooth (Creaser, 1930), Sporn (Brtek, 1974)): A digitiform
process arising from the lateral lamella in the
anteroventral direction.
3. inner lamella: A blade on the inner dorsal side of
the thumb, which folds medioventrally and ends
obliquely in an irregular border. Posteriorly, the
inner lamella is connected to the base of the hand
or to the dorsoposterior inner side of the finger.
Therefore, a cavity delimited by both the lateral
and inner lamellae is usually found in the dorsal
basal part of the thumb.
4. teeth (Barnard, 1924, 1929)(= lobo, tuberculo, processu (Daday, 1908, 191Oa,b), processes (Mackin,
1942)). They are variously shaped projections situated on the dorsal side of the proximal part of the
finger. Although these projections can arise from
the lateral, dorsal and inner borders, only the number and shape of those on the inner border are normally taken as being of diagnostic importance.
Male genitalia
According to Linder (1941:232) a linguiform outgrowth may develop on the second genital segment,
lateral to the nonretractile base of each penis (Fig.
7 D). It was figured by Claus (1886, Taf. X, Figs
12, 13). It is soft in consistency and shorter than the
basal part of the penis. Its function is unknown. The
absence of such a structure has been reported in S. linderi Moore and S. mackini Moore by Moore (1966),
and in S. proboscideus by Brendonck (1989). Similar
structures have been reported for a number of species
of Branchinella Sayce, 1903 (Linder, 1941:242; Geddes, 1981). The non-retractile basal part of the penes
is a flexible tubular structure, the basal inner side of
which is invariably armed with a digitiform appendix
covered by a set of spinules (Fig. 7 C, D). Although the
length of the basal part of the penes is variable among
as well as within species, its tip typically lies under
1886; Brtek, 1974), S-shaped antennal process (Brendonck & Belk, 1993; Hamer et ai., 1994 a,b)), protruding just above of the apical joint (Figs 1 C-G, 2
A,7 A), consists of two main parts: 1) A peduncle (=
median part or section (Sars, 1898, 1899, 1900, 1905),
articulus secundus (Daday, 1908), articulus medius
(Daday, 1910a,b), second joint (Barnard, 1924), second segment (Mackin, 1942), basale und mittlere Teil
des antennalen Fortsatzes (Brtek, 1974)) (Fig. 2), and
2) a scleroid hand (Sars, 1899, 1900, 1905)(= Zange
(Claus, 1886), chela (Sars, 1898), terminal part or section (Sars, 1899, 1900, 1905), articulus apicalis or
ultimus (Daday, 1908, 191Oa,b), third joint (Barnard,
1924), third segment or scissors (Mackin, 1942), terminale scherenartige Teil des antennalen Fortsatzes
(Brtek, 1974)) (Fig. 2).
In the adult stage, the peduncle is a cylindrical, robust, unigeniculated or bigeniculated structure,
which, depending on the species, is of determinate
length. Comparing this length with the standard length,
basal joint length, and apical joint length, the peduncle
can be defined as short, intermediate, or long (see
Species groups of Streptocephalus). The peduncle,
carried in retracted position except during amplexus,
presents a geniculation near the middle of its extension
(Figs 2 A, 7 A). A second geniculation, at the base of
the hand, rotated more than 50 ° , is present in all long
peduncles (e.g. Fig. 6, E). In only one of the species
groups with an intermediate length peduncle (the cafer
group), the base of the hand exhibits a rotation of c.
50° (e.g. Fig. 6 D). In the other species groups with
intermediate or short peduncles, a rotation of no more
than 40° occurs (e.g. Fig. 6 B). The peduncle can be
ornamented with different and variable processes. A
pad-like protuberance, the pulvinus, is situated on the
laterobasal side of the peduncle (Fig. 7 A, B). Although
the pulvinus is a feature of most species with short and
intermediate peduncles, three species with long peduncles exhibit such a structure.
The basic plan of the hand includes 3 primary
parts: (1) a dorso-Iateral thumb (Barnard, 1929) (=
outer dactylus (Sars, 1899), anterior digitus (Sars,
1898, 1900), digitus exterior or superior (Daday, 1908,
1910a,b), anterior prong (Barnard, 1924), outer part
(Creaser, 1930), Dorsalarm (Brtek, 1974)) (Figs 1 EG, 2, 6); (2) a ventral-inner finger (Barnard, 1929) (=
inner dactylus (Sars, 1899), digitus interior or inferior (Daday, 1908, 191Oa,b), posterior prong (Barnard,
1924), inner part (Creaser, 1930), Ventralarm (Brtek,
213
1974)) (Figs 1 E-G, 2, 6); and (3) a base of the hand
(= palm (Sars, 1898)), at which both former structures
are attached (Fig. 2).
From the basic plan of the hand the next structures
can be derived (Fig. 2, B):
l.lateral lamella (= lamina lateralis (Daday, 1908,
1910a, b)): The blade of the thumb which folds
lateroventrally along the ventral base of the thumb.
2. spur (Mackin, 1942)(= lower lappet (Sars, 1899),
processu (Daday, 1908), lamina lateralis (Daday,
191Oa,b), posterior process (Barnard, 1924) posterior prong (Barnard, 1929), elongate tooth (Creaser, 1930), Sporn (Brtek, 1974)): A digitiform
process arising from the lateral lamella in the
anteroventral direction.
3. inner lamella: A blade on the inner dorsal side of
the thumb, which folds medioventrally and ends
obliquely in an irregular border. Posteriorly, the
inner lamella is connected to the base of the hand
or to the dorsoposterior inner side of the finger.
Therefore, a cavity delimited by both the lateral
and inner lamellae is usually found in the dorsal
basal part of the thumb.
4. teeth (Barnard, 1924, 1929)(= lobo, tuberculo, processu (Daday, 1908, 191Oa,b), processes (Mackin,
1942)). They are variously shaped projections situated on the dorsal side of the proximal part of the
finger. Although these projections can arise from
the lateral, dorsal and inner borders, only the number and shape of those on the inner border are normally taken as being of diagnostic importance.
Male genitalia
According to Linder (1941:232) a linguiform outgrowth may develop on the second genital segment,
lateral to the nonretractile base of each penis (Fig.
7 D). It was figured by Claus (1886, Taf. X, Figs
12, 13). It is soft in consistency and shorter than the
basal part of the penis. Its function is unknown. The
absence of such a structure has been reported in S. linderi Moore and S. mackini Moore by Moore (1966),
and in S. proboscideus by Brendonck (1989). Similar
structures have been reported for a number of species
of Branchinella Sayce, 1903 (Linder, 1941:242; Geddes, 1981). The non-retractile basal part of the penes
is a flexible tubular structure, the basal inner side of
which is invariably armed with a digitiform appendix
covered by a set of spinules (Fig. 7 C, D). Although the
length of the basal part of the penes is variable among
as well as within species, its tip typically lies under