5.4 Neomysis monticellii Colosi, 1924
Neomysis monticellii Colosi, 1924: pp. 6, 7, figs.
7-9 - Tattersall, 1951: p. 248 - Tattersall, 1955:
pp. 171, 172, figs. 43a, 44a-c - Mtiller, 1993:
p. 240 (world catalogue).
Body length -
females: 6.4-10.5 mm (11 specimens)
males: 6.5 mm (13 specimens)
Female. Body small; posterodorsal margin of
carapace reaching anterior edge of 8th thoracic
somite. Anteriorly, dorsal plate bearing very
short, triangular frontal plate, not covering eyes.
Apex of rostrum slightly rounded and with acute
extremity, bending downwards at the base of ocular peduncles. Eyes large and darkly pigmented. Antennules with typical 3-segmented peduncle; 2nd segment 1/3 length oflast. Antennae
with relatively large peduncle, surpassing extremity of antennular peduncles. Scale lanceolated, both margins of which covered with setules;
length of scale extending beyond antennular peduncles by 1/5. Pleon with 6th segment 1/3longer than 5th. Uropodal endopodite somewhat
longer than telson; exopod longer than telson by
1/3. Ventral side of endopodite bearing 2 spines,
in correspondence to distal margin of statocysts.
Of the 2, shorter spine on external margin. Telson about 1.5 times longer than last somite of
pleon, elongated, entire, and with pointed extremity. Along margins of either side are 30-32
equal or subequal spines; extremity bears 2 pairs
of spines. 1st pair of more outer spines are longer
than spines on margins: 2nd pair of inner spines
shorter than 1st pair and those on margins.
Male. Antennules bearing characteristic protuberance on ventral si de at base of 2 flagellae. Protuberance well developed and as long as last
segment of antennular peduncle; lobate and
bearing thick tuft of long setules. Antennal scale
reaching apex oflobe. 4th pleopod long; exopod
4 times longer than endopod, extending somewhat beyond apex of telson. Exopod consisting
in two segments; 1 st segment almost 4 times
longer than 2nd. Same pleopod bearing 2 large
spinulated setules of unequallength at distal extremity. Endopod with numerous setules on inner margin; outer margin bearing small tubercle
with 4 setae, bending over exopod.
Remarks
The protuberance on the distal ventral si de of the
antennular peduncle of the male is very stout, !obate and bristly. Colosi (1924) reported that a
distinct distal articulation was visible on the
scale of the antenna. However, in accordance
with Tattersall (1955), this was not observed in
the present study. My observations also agree
with Tattersall and not with Colosi with regards
to the 2 spines on the ventral si de of the uropodal
endopodite. The latter author reported the presence of a single spine in this position. The spines
observed on the outer margins of the telson
ranged from 30-32 as compared to 23-28 reported by Colosi. Tattersall does not make any mention of the number of these spines.
Distribution.
N. monticellii has formerly been reported only
by Colosi (1924) and Tattersall (1955). The former author found the species at Cape Virgin
(Straits ofMagellan) but did not report the depth
Neomysis monticellii Colosi, 1924: pp. 6, 7, figs.
7-9 - Tattersall, 1951: p. 248 - Tattersall, 1955:
pp. 171, 172, figs. 43a, 44a-c - Mtiller, 1993:
p. 240 (world catalogue).
Body length -
females: 6.4-10.5 mm (11 specimens)
males: 6.5 mm (13 specimens)
Female. Body small; posterodorsal margin of
carapace reaching anterior edge of 8th thoracic
somite. Anteriorly, dorsal plate bearing very
short, triangular frontal plate, not covering eyes.
Apex of rostrum slightly rounded and with acute
extremity, bending downwards at the base of ocular peduncles. Eyes large and darkly pigmented. Antennules with typical 3-segmented peduncle; 2nd segment 1/3 length oflast. Antennae
with relatively large peduncle, surpassing extremity of antennular peduncles. Scale lanceolated, both margins of which covered with setules;
length of scale extending beyond antennular peduncles by 1/5. Pleon with 6th segment 1/3longer than 5th. Uropodal endopodite somewhat
longer than telson; exopod longer than telson by
1/3. Ventral side of endopodite bearing 2 spines,
in correspondence to distal margin of statocysts.
Of the 2, shorter spine on external margin. Telson about 1.5 times longer than last somite of
pleon, elongated, entire, and with pointed extremity. Along margins of either side are 30-32
equal or subequal spines; extremity bears 2 pairs
of spines. 1st pair of more outer spines are longer
than spines on margins: 2nd pair of inner spines
shorter than 1st pair and those on margins.
Male. Antennules bearing characteristic protuberance on ventral si de at base of 2 flagellae. Protuberance well developed and as long as last
segment of antennular peduncle; lobate and
bearing thick tuft of long setules. Antennal scale
reaching apex oflobe. 4th pleopod long; exopod
4 times longer than endopod, extending somewhat beyond apex of telson. Exopod consisting
in two segments; 1 st segment almost 4 times
longer than 2nd. Same pleopod bearing 2 large
spinulated setules of unequallength at distal extremity. Endopod with numerous setules on inner margin; outer margin bearing small tubercle
with 4 setae, bending over exopod.
Remarks
The protuberance on the distal ventral si de of the
antennular peduncle of the male is very stout, !obate and bristly. Colosi (1924) reported that a
distinct distal articulation was visible on the
scale of the antenna. However, in accordance
with Tattersall (1955), this was not observed in
the present study. My observations also agree
with Tattersall and not with Colosi with regards
to the 2 spines on the ventral si de of the uropodal
endopodite. The latter author reported the presence of a single spine in this position. The spines
observed on the outer margins of the telson
ranged from 30-32 as compared to 23-28 reported by Colosi. Tattersall does not make any mention of the number of these spines.
Distribution.
N. monticellii has formerly been reported only
by Colosi (1924) and Tattersall (1955). The former author found the species at Cape Virgin
(Straits ofMagellan) but did not report the depth