The Agononida incerta species complex unravelled (Crustacea: Decapoda: Anomura: Munididae)
Author
Poore, Gary C. B.
Author
Andreakis, Nikos
text
Zootaxa
2012
3492
1
29
journal article
10.5281/zenodo.211238
1eecff0a-945d-4482-b199-adbeb1e33dc7
1175-5326
211238
086B5A51-BD5D-4B84-B2CE-82B118A71C0B
Agononida africerta
n. sp.
(
Figs 2
D, E, 3C, 8)
?
Munida incerta
.—
Kensley 1977
: 162
.—
Baba 1990
: 963
–964.—
Tirmizi 1966
: 205
, fig. 22.
Material examined
.
Holotype
.
MOZAMBIQUE
.
Mozambique
Channel. 25°13ʹS, 35°18ʹE,
480–503 m
,
10.04.2009
(MAINBAZA stn CP3135),
MNHN
IU-
2008-10438 (female, cl
22. 4 mm
).
Paratypes
.
MOZAMBIQUE
.
Mozambique
Channel. 23°31ʹS, 35°50ʹE,
446–475 m
,
11.04.2009
(MAINBAZA stn CP3142),
MNHN
IU-
2008-10192 (supermale, cl
31 mm
);
MNHN
IU-
2008-10440 (female, cl
26 mm
);
MNHN
IU-
2008-10441 (female, cl
24 mm
);
MNHN
IU-
2008-10442 (male, cl
17 mm
). 24°11.71ʹS, 35°42.3ʹE,
505–506 m
,
15.04.2009
(MAINBAZA stn CC3164),
MNHN
IU-
2008-10435 (female, cl
13.8 mm
). 24°11.71ʹS,35°
42.3E
,
505–507 m
,
15.04.2010
(MAINBAZA stn CC3165),
MNHN
IU-
2008-10436 (male, cl
15.1 mm
). 24°11.71ʹS, 35°42.3ʹE,
505–508 m
,
15.04.2011
(MAINBAZA stn CC3166),
MNHN
IU-
2008-20703. (5, females, cl
6–12 mm
;
3 males
, cl.
10–17 mm
). 25°13ʹS, 35°18ʹE,
480–503 m
,
10.04.2009
(MAINBAZA stn CP3135),
MNHN
IU-
2008- 10191 (female, cl
18 mm
);
MNHN
IU-
2008-10437 (male, cl 18.8);
MNHN
IU-
2008-20704 (many juveniles, cl ~
18 mm
). 25°12ʹS, 35°17ʹE,
503–505 m
,
10.04.2009
(MAINBAZA stn CP3136),
MNHN
IU-
2008-20705 (
3 females
, cl
12–24 mm
;
2 males
, cl
12 mm
);
MNHN
IU-
2008-10190 (female, cl
17 mm
);
MNHN
IU-
2008-10439 (female).
Other material.
MADAGASCAR
. 12°44.8ʹS, 48°10.6ʹE, 570–
563 m
, 0 5.03.1971 (Crosnier stn P1-5),
MNHN
Ga-685 (
3 females
;
13 males
, cl to
23 mm
).
FIGURE 4
.
Agononida incerta
(Henderson, 1888)
Holotype, juvenile female. A, dorsal view; B, telson. Scale bars = 10 mm.
Diagnosis
. Telson anterolateral margin sinusoidal, concave and smooth over anterior 60%, remainder sometimes separated by notch, strongly convex, margin almost longitudinal anterior to transverse suture, with crenellate margin. Pereopodal 2–4 dactyli about 6 times as long as greatest basal width, 15–25 (median about 20, 8 exceptional); pereopod 3, 4–9 (median 6); pereopod 4, 1–3. Pereopod 4 merus with 1–4 spines proximally on upper face.
Descriptions
.
Ovigerous female. Based on MNHN IU2008–10438, cl
22.4 mm
.
Carapace 0.9 times as long as greatest width. Frontal margin inclined posteriorly at 18° from midline. Rostrum spiniform, 0.45 length of carapace (both measured from base of supraocular spines); supraocular spine 0.65 length of rostrum (both measured from base of rostrum). Thoracic sternite 3 0.48 width of sternite 4; midlength of sternal plastron (sternites 4–7) 0.6 width of sternite 7. Telson greatest width 1.8 times midlength; anterolateral margin sinusoidal, concave and smooth over anterior 60%, remainder separated by notch, strongly convex, margin almost longitudinal anterior to transverse suture, with crenellate margin; lateral margin convex, narrower posteriorly than anteriorly.
Eyes with maximum corneal diameter 0.9 basal width of supraocular spines. Maxilliped 3 ischium 0.6 times as long as merus.
Pereopod 1 (cheliped) of typical adult form, covered with flat squamae fringed with short setae; 3.6 times as long as carapace, merus 0.9 times as long as carapace, carpus 0.7 times as long as merus, propodus 1.9 times as long as merus, fingers 0.5 times as long as total propodus length. Merus with 1+9 spines along upper margin, 4 spines along mesial face, 17 spines along lateral face, with distal spine and 1–3 spine-like squamae on lower margin; propodus spines with marginal spines, with 6 spines on upper margin, with 1+4 spines along mesial face, with 1+3 spine on lateral face near base of dactylus, with 1–3 oblique spines along lower margin plus 1–3 spines on lower lateral face; dactylus cutting edge with ridge of c. 50 denticles.
Minor pereopod 1 with only minor differences.
FIGURE 5
.
Agononida incerta
(Henderson, 1888)
Holotype, juvenile female. A, telson and uropod; B, sternal shield; C, maxilliped 3; C, left antennule and antenna, ventral view; E, free dactylus (probably of pereopod 2, with 9 robust setae); F, carpus–dactylus, pereopod 4 (with 1 robust seta). Scale bar=5 mm.
Pereopod 2 2.9 times carapace length, merus 1.3 times carapace length, 8.8 times a long as greatest width, carpus 0.24 times as long as merus, propodus 0.6 times as long as merus, dactylus 0.6 times as long as propodus; merus with 1+16–20 spines along extensor margin, with 1+8 spines along flexor margin; carpus with 1+1–2 spines along extensor margin; dactylus evenly curved over distal two-thirds, 5.9 times as long as greatest basal width, with row of 20 robust setae distal to heel of flexor margin.
Pereopod 3 2.9 times carapace length, merus 1.3 times carapace length, 7.5 times a long as greatest width, carpus 0.24 times as long as merus, propodus 0.6 times as long as merus, dactylus 0.6 times as long as propodus; merus with 1+16–20 spines along extensor margin, with 1+9–10 spines along flexor margin; carpus with 1+3 spines along extensor margin; dactylus evenly curved over distal two-thirds, 6.1 times as long as greatest basal width, with row of 4 robust setae distal to heel of flexor margin.
Pereopod 4 2.8 times carapace length, merus 1.1 times carapace length, 6.7 times a long as greatest width, carpus 0.3 times as long as merus, propodus 0.7 times as long as merus, dactylus 0.5 times as long as propodus; merus with 1+15–18 spines along extensor margin, with 1+8 spines along flexor margin, merus with 1–4 spines proximally on upper face; carpus with 1+2 spines along extensor margin; dactylus more gently curved than dactyli 2 or 3, distally less setose, 6.1 times as long as greatest basal width, dactylus with 2 robust seta(e) distal to heel of flexor margin.
Male. Based on MNHN IU2008–10437, cl 19.0 mm.
Telson anterolateral margin much as in female. Pereopod 1 (cheliped) merus 1.1 times as long as carapace, carpus 0.5 times as long as merus, propodus 1.3 times as long as merus, fingers 0.55 times as long as total propodus length. Merus with 1+8 spines along upper margin, 5–8 spines along mesial face, 14 spines along lateral face.
FIGURE 6
.
Agononida incerta
(Henderson, 1888)
Western Australian specimens. Male, NMV
J56025
: A, habitus; B, telson; C, dactyli of pereopods 2–4 with detail of robust setae at greater magnification (most broken); D, cheliped in lateral view. Ovigerous female, NMV
J55021
.
E
, Habitus;
F
, telson. Scale bars = 10 mm.
FIGURE 7
.
Agononida incerta
(Henderson, 1888) Supermale
, ZMUC CRU11555. A, B, habitus in dorsal and lateral views; C, telson (scale bar=5 mm); D, left dactyli of pereopods 2–4 with detail of robust setae at greater magnification; E, F, major cheliped in lateral and mesial views.
FIGURE 8
.
Agononida africerta
n. sp.
Holotype, female, MNHN IU-2008-10438. A, habitus; B, telson; C, dactyli of pereopods 2–4 with detail of robust setae at greater magnification. Paratype, male, MNHN IU-2008-10437. D, telson. Scale bar = 10 mm.
Pereopod 2 3.6 times carapace length, carpus 0.23 times as long as merus, dactylus 0.7 times as long as propodus; dactylus with row of 25 robust setae distal to heel of flexor margin.
Pereopod 3 3.1 times carapace length, dactylus 0.7 times as long as propodus; dactylus with row of 4 robust setae distal to heel of flexor margin.
Pereopod 4 3 times carapace length, dactylus 0.6 times as long as propodus; dactylus with 3 robust setae distal to heel of flexor margin.
Colour
. From photo by T.Y. Chan (MNHN IU-2008-10192, supermale;
Fig. 3
C): carapace and abdominal somites 1–4 generally orange, stronger around bases of spines and rostrum. Spines and squamae of pereopods more strongly coloured than elsewhere. Transverse broad orange bands distally on meri of pereopods 1–4, proximally on carpi of pereopods 1–4, subdistally on carpus of pereopod 1, proximally on propodus of pereopod 1, at propodusdactylus articulation of pereopod 1, and along most length of propodi of pereopods 2–4, stronger distally.
Variation
. Five of
40 specimens
up to cl
31 mm
[plus many juveniles] from MAINBAZA samples at MNHN were examined in greater detail. In these, the numbers of robust setae distal to the heel on the flexor margin of the dactyli of pereopods 2–4 vary, even from one side to the other: pereopod 2, 15–22 (8 exceptional, median about 20); pereopod 3, 4–9 (median 6); pereopod 4, 1–2.
Distribution
. Off
Madagascar
and eastern
Mozambique
, 13°S–25°S;
446–
570 m
.
Etymology
.
africerta
, a combination from Africa and
incerta
.
Remarks
. The telson of
Agononida africerta
differs slightly but consistently from that of the Western Australian species,
A. indocerta
which is resembles. Whereas in the adult male of
A. indocerta
the anterolateral lobe of the telson projects strongly and even tapers posteriorly, that of
A. africerta
is more evenly rounded. The counts of robust setae on the pereopodal dactyli are fewer than in
A. indocerta
(which has median numbers of 35, 17 and 10 on pereopods 2–4 respectively. The dactyli themselves are narrower and more tapering than in
A. indocerta
.
These two are the only species in which 1–4 facial spines are usually (but not always) found on the upper surface of the merus of pereopod 4. Both species also, the propodus of the cheliped has 1–3 spines on the lower lateral face, between the spines on the lateral face near the base of the dactylus and the spines on the lower margin. None of these are present in supermales. The coloration of the fresh specimen of
A. africerta
and the preserved specimens of
A. indocerta
are similar, in as far as this comparison will allow.
Barnard (1925
;
1950
) reported
Munida incerta
from
Portuguese East Africa
, now
Mozambique
(
25°56´S
,
32°52´E
), at a depth of
17 m
.
His description is general and drawing only of the anterior carapace. The occurrence of this species or of
A. africerta
at this shallow depth is improbable. However,
Kensley (1977)
also reported
M. incerta
from
280–454 m
off southern
Mozambique
and
Baba (1990)
recorded numerous specimens of the same species from
Madagascar
at
394–
700 m
.
Tirmizi (1966: 205, fig. 22)
provided figures of a specimen off
Zanzibar
,
421–658 m
, but nothing to characterise the species. While none of these been examined by us, it is possible they all referred to
A. africerta
.
Agononida africerta
is genealogically most related to
A. indocerta
, known records coming from opposite sides of the Indian Ocean. This relationship is supported by shared morphological characters.