166 
Pereopods. Slender and long (Fig. 23, PE1—7), dactylus with 
simple dactylar seta, apically with some rudiments of plumes, long 
inner claw (Fig. 23, Dac), pereopod | carpus with antenna-grooming 
brush and ornamental sensory spine with hand-like apex (Fig. 23, 
Sc1), distal sensory spine of basis long. Sexual differentiation. Male 
pereopods | to 3 with setal brushes on propus to merus, carpus 
enlargement subequal in all 3 pereopods, merus of pereopod 5 and 6 
with set of sensory spines of different length, proximal spine of 
merus 6 on a slight hump, directed distally, pereopod 7 merus 
medially with proximal sensory spine, two long spines on halflength, 
two shorter ones more proximally, ischium with dense setal brush, 
medio-distal lobe with dense cover of small cuticular trichiae, 
rostrally with a slight depression. 
Pleopods. Pleopod endopodites slightly bilobate, exopodites with 
up to 10 sensory spines laterally and minute pectinate scales medi- 
ally, protopodites 3 to 5 without lateral rudiments of epipodites, no 
respiratory areas discernible (Fig. 24, PL1—5). Sexual differentia- 
tion. Male pleopod | exopodite triangular with long lateral point, 
lateral margin straight, small wrinkle proximally of point, endopoite 
slender with short subapical protrusion laterally, apex drawn out 
with 5 spines rostrally, caudally with dense row of spines. Pleopod 
2 exopodite with sinuous lateral margin, endopodite with slightly 
pointed apex. 
Uropod. As in generic diagnosis. 
Genital papilla. Ventral shield only slightly surpassing terminal 
spatula (Fig. 24, Gen). 
DISCUSSION 
Most of the species of Ischioscia Verhoeff, 1928 found in Venezuela 
belong into the vicinity of the well-known J. variegata (Dollfus, 
1893). For a detailed description of this species cf. Leistikow 
(1997). I. fasciifrons sp.nov. is distantly related to the others; it 
differs in the lack of a setal brush on the male pereopod 7 ischium 
which bears a transverse furrow medio-rostrally instead of this 
brush, the distal lobe is rather inconspicuous. Another autapomorphy 
of this species is the simple dactylar seta instead of an apically 
plumose one. The apex of the male pleopod 1 endopodite is obtuse 
with a set of very small spines terminally, quite distinct from the 
medio-caudal row of spines, the exopodite is only slightly incised, 
with a short protrusion. The structure of the male pleopod | is similar 
to /. colorata sp.nov. from the coastal region of Caracas, this species 
differs in the presence of prominent setal fields in the carpus and 
merus of pereopod 4, merus of pereopod 5 and a setal brush on the 
ischium of pereopod 7. Thus, /. colorata is a member of the 
variegata-group of species as defined by Leistikow (1997). This 
species is further characterized by the shape of the apex of male 
pleopod 2 endopodite, which is an autapomorphy for the species. 
The maxillula bears a single subapical tooth like J. hirsuta sp.nov, 
and /. fasciifrons sp.noy., this is in contrast to the two teeth in /. 
paride sp.nov., J. guamae sp.noy., and J. trifasciata sp.nov. 
In /. trifasciata, both teeth are apically serrate while in the others 
the teeth are acute. Besides, the simplified dactylar seta, the shape of 
the male pleopod | and the setation of male merus 7 are autapo- 
morphies of 1. trifasciata. 
I. hirsuta is characterized by the following derived character 
states: a long-haired setal brush on male ischium 7, a hand-like 
subdistal sensory spine of propus 1, and the long tricorn-like setae 
on the pereonites. 
For /. guamae, the most distinct character is the setation of the 
male merus 7, with the four sensory spines all in the proximal half of 
A. LEISTIKOW 
hte 





Fig. 25 Schematic drawing of the male merus 7, indicating the position 
of sensory spines along medial margin in the ground pattern of the 
variegata-group within the genus /schioscia Verhoeff, 1928. 
the article, one of the smaller stands alongside the long proximal 
sensory spine. Another autapomorphic character is the caudolateral 
position of the remainder of the row of spines on the male pleopod 
1 exopodite. 
The autapomorphies for /. pariae are the peculiar shape of the 
dactylar seta with club-like apex instead of the feathery one, and the 
reduction of the number of sensory spines on the male merus 7 to 
three along the medial border. 
The setation of the male merus 7 allows easy recognition of the 
Venezuelan species of /schioscia. In the ground pattern of the male 
merus 7, the arrangement of sensory spines along the medial margin 
from proximally to distally is a long proximal one, two smaller ones 
distally of the former, another sensory spine even more distally and 
then a gap which is terminated distally by the medio-distal set of 
about three long sensory spines, described by the formula 
[1+2+1+0+3] which can be found in e.g. J. martinae Leistikow, 
1997, I. plurimaculata Leistikow, 1999 or I. bolivari Vandel, 1968 
(fig. 25). This formula is varying in the different species of Ven- 
ezuela as follows: 
I. hirsuta [14+(1+2)+(1+2)+1+3] 
I. colorata {1+2+1+1+3], 
I. pariae {(1+1)+0+1+0+3] 
I. guamae {(1+1)+1+1+0+3] 
I. trifasciata [1+1+3+0+3] 
I. variegata [0+(1+1)+0+0+3]. 
I. fasciifrons does not fit this sheme as it differs in other characters 
as stated above. The position of the long spine alongside a single 
short one may be a synapomorphy of /. pariae and I. variegata, this 
assumption is supported by the similar shape of the genital papilla, 
which in both species has a long pointed ventral shield — much 
longer than the termial spatule with the laterally placed orifices. 
From an ecological point of view, the genus /schioscia is adapted 
to many different types of habitat. The autochthonous habitat is the 
moist rain forest but the members of this genus have adapted to 
secondary growth, cattle pastures and other disturbed environments. 
An interesting behavioural difference has been observed in /. pariae 
and /. variegata both of which are capable of jumping. The former 
was observed to jump about 5 cm; /. variegata can jump even wider, 
up to 20 cm and hence can easily escape predators like spiders and 
