Cyrtomaia micronesica Richer
publication ID |
https://doi.org/ 10.11646/zootaxa.3764.3.3 |
publication LSID |
lsid:zoobank.org:pub:F1B0E174-89C5-4A9E-B7DA-C5E27AF624D3 |
DOI |
https://doi.org/10.5281/zenodo.6132369 |
persistent identifier |
https://treatment.plazi.org/id/03EB595D-FF94-757C-FF66-F9AD4CADFEBF |
treatment provided by |
Plazi |
scientific name |
Cyrtomaia micronesica Richer |
status |
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Cyrtomaia micronesica Richer View in CoL de Forges & Ng, 2007
( Figs. 22–25 View FIGURE 22 View FIGURE 23 View FIGURE 24 View FIGURE 25 , 26A–E View FIGURE 26. A – E )
Cyrtomaia micronesica Richer de Forges & Ng, 2007: 62, figs. 1–4, 5B, D [type locality: off Haputo, Guam, 270 m].—Ng et al. 2008: 111 (list).
Material examined. RV “Natsushima”, NT10-13 cruise, ROV “Hyper-Dolphin”, dive #1165, Northeast Nikko Seamount, 23°06.748’N, 142°21.554’E, 637 m, 31 July 2010, manipulator, 1 male (39.0 × 43.5 mm), JAMSTEC 081529 -1; same dive, 23°06.709’N, 142°21.873’E, 553 m, 1 male (42.5 × 50.5 mm), JAMSTEC 081529 -2.
Coloration in life. Dorsal side of body and appendages generally tan.
Distribution. Previously known from Guam and Palau, at depths of 210– 600 m. The present specimens extend the geographical range of this rarely collected species to the Nikko Seamount, south of Ogasawara Islands, at depths of 553– 637 m. New records for Japanese marine fauna.
Ecology. We often encountered this species during the dive, though only two specimens were collected. The individuals were found to be slowly wandering on rock substrates.
Remarks. The larger male differs from the smaller male in the more elongate chelipeds with more stout chelae; spines on segments are less strong and/or less acute in the larger specimen than in the smaller specimen. The variation seems to be size-related.
The present specimens agree generally with the original description of Cyrtomaia micronesica in the following diagnostic characters: carapace surfaces finely granular, with small tubercles on branchial regions ( Fig. 23 View FIGURE 23 A); carapace armature including pseudorostral spines distinctly longer than rostrum, very long, smooth, slightly divergent protogastric spines, tiny median gastric spine, strong, acute postocular spines, very small orbital intercalated spines, very small anterior branchial spines, and two cardiac spines reduced to small tubercles; epibranchial and posterior branchial spines reduced to minute tubercles, intestinal spine also reduced to very low protuberance ( Figs. 23 View FIGURE 23 A, B, 24); blunt longitudinal ridge connecting orbital intercalated spine and protogastric spine present ( Fig. 23 View FIGURE 23 B); eyestalk short, only reaching to orbital intercalated spine, with minute tubercle near base of cornea ( Figs. 23 View FIGURE 23 B, 24); second pereopod longer than cheliped, merus bearing slender spines on anteroventral surface arranged in two rows ( Fig. 22 View FIGURE 22 ); third pereopod shorter than second pereopod, though similar in general armature ( Fig. 22 View FIGURE 22 ); fourth and fifth pereopods unarmed except for prominent dorsodistal spine on each merus ( Fig. 22 View FIGURE 22 ); and first abdominal somite with one small median tubercle ( Fig. 23 View FIGURE 23 A). On the other hand, the cheliped of the holotype appears intermediate between the present specimens in the development of spines and the shape of the chela (cf. Richer de Forges & Ng 2007: fig. 4B, C; Figs. 25 View FIGURE 25 A, B); the basal segment of the antennal peduncle is armed with three spines in the present specimens ( Fig. 26A View FIGURE 26. A – E ), rather than four in the type description. Richer de Forges & Ng (2007) cited the length of the cheliped in differentiating C. micronesica and C. cornuta Richer de Forges & Guinot, 1988, but the examination of the present specimens shows that the length of the cheliped increases with growth in C. micronesica .
Although the male first gonopod of the present specimens ( Fig. 26B–E View FIGURE 26. A – E ) agrees well with the figure provided by Richer de Forges & Ng (2007), the original description of the distal part of the male first gonopod may be misleading. The distal part of the male first gonopod of this species is actually flattened, forming a rounded apex in the distal view ( Fig. 26E View FIGURE 26. A – E ); the acuteness of the tip mentioned in the original description actually reflects the strong degree of the compression.
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.
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