Odontozona arbur Saito, Okuno and Anker, 2017

Lee, Seok Hyun, 2020, First record of Odontozona arbur (Decapoda: Stenopodidae: Odontozona) from Korea, Journal of Species Research 9 (3), pp. 247-250 : 247-248

Odontozona arbur Saito, Okuno and Anker, 2017

ăê꼬ŔḡǐNj우 (신ÿ)

Odontozona arbur Saito, Okuno and Anker, 2017: 27 , figs. 1 - 8A - C, 13A - D.

Odontozona ensifera : Minemizu, 2013: 19; Goy, 2015: 320 , figs. 15 - 17 [not O. ensifera ( Dana, 1852) ].

Odontozona sculpticaudata : Goy, 2015: 329 , fig. 22 (in part) [not O. sculpticaudata Holthuis, 1946 ].

Odontozona sp. 2 : Okuno, 2007: 58.

Odontozona sp. 4 : Minemizu, 2013: 21.

Material examined. 1 ovig. $(pocl 3.8 mm), Munseom Is. in Seogwipo , Jejudo Is., 28 Jun 2018, Lee SH, scuba in about 14 m depth .

Description. Rostrum ( Fig. 1A ) straight; dorsal margin with 7 teeth; ventral margin with 4 teeth; lateral margins with minute spine at about a third of proximal part.

Carapace ( Fig. 1A ) supraorbital region with various sized spines; orbital margin concaved, with orbital spine; antennal lobe rounded, with large, acuminate, submarginal antennal spine; pterygostomial margin produced anteriorly with large, sharped, submarginal branchiostegal spine and 3 spines; cervical groove distinct, posterior margin with cincture of large, slender spines; posterocervical groove indistinct dorsally, distinct laterally, posterior margin with spines.

Abdomianl somite ( Fig. 1D, E ) sculptured; second somite divided into 2 parts by transverse carina approached to about mid height of lateral surface of pleuron; third somite largest, distinct transverse carina on tergum, anterior part divided into 2 parts by transverse carina approached to about one third height of pleuron; fourth and fifth somites with short transverse depressions, lateral surface with small spines, ventral margins with spines; sixth somite with central transverse grooves on medial part, rows of transverse spines on posterolateral part of dorsal surface, lateral surface with 3 spines, posterior margin with long, sharp spines.

Telson ( Fig. 1E ) elongated, lance-formed, gradually tapering digitally; dorsal surface with shallow depression, with 5 pairs of mediolateral spines, 1 pair of proximal spines, 7 submedial spines; lateral margins with 1 pair of proximal and medial spines; subposterior margin with 2 spines.

Eye ( Fig. 1A ) well developed; eyestalk with 6 spines.

Antennular peduncle ( Fig. 1B ) stylocerite omitted; with proximal and distal spines on first segment, 5 spines on second segment.

Antennal scale ( Fig. 1C ) setae omitted; approximately 3.5 time longer than broad; lateral margin concaved, with 9 spines.

Third maxilliped ( Fig. 1F ) moderately slender, setae omitted; dactylus setose, tapering distally; propodus subrectangular with long setae on lateral margins; carpus subrectangular, unarmed; merus with 5 spines on dorsolateral margin and 10 spines on ventral margin; ischium subrectangular, with 7 spines on ventromesial margin; exopod with long flagellum, approaching middle part of merus.

Pereopods ( Fig. 1G - K ) with first pereopod ( Fig. 1G ) shortest, subcylindrical; fingers as long as palm, with setae distally, cutting edges unarmed; palm subcylindrical slightly swollen; carpus slightly longer than chela; ventral margin with spine and setae on subdistal part. Second pereopod ( Fig. 1H ) longer than first pereopod, slender, all segments unarmed; finger slightly shorter than palm; palm subcylindrical slightly swollen; carpus subrectacular, 14 times longer than maximal width. Third pereopod ( Fig. 1I ) longest, robust; fingers 14 times longer than maximal width, movable finger with 2 spines on dorsal surface, fixed finger with 2 teeth on proximal cutting edge; palm subcylindrical, with 11 spines on dorsal margin, ventral margin with spinules; carpus subcylindrical, widening distally, slightly shorter than chela, dorsal margin with 2 rows of 11 spines, ventral margins with 7 spines; merus subrectacular, about 6 times longer than broad, dorsal margin with 9 spines on a row, ventral margin with 2 spines on medial and distal part. Fourth and fifth pereopods ( Fig. 1J, K ) long, slender, similar in shaped; each dactyli short, compressed, biunguiculate; propodi subrectacular, segmented, ventral margins with movable spines; carpi longest, subrectacular, segmented, ventral margins with movable spines; meri subrectacular, unsegmented, unarmed.

Uropod ( Fig. 1E ) with exopod, with 8 spines on lateral margin; endopod with 4 spines on proximal to medial part of lateral margin.

Color in life. Body and appendages generally reddish white, semitransparent and scattered reddish chromatophores. Dactylus of first to third pereopods white. Lateral and posterior margins of abdominal somites and posterior margins of telson and uropod with reddish chromatopores.

Habitat. The present specimen of O. arbur was collect- ed from under rocks at about depth 14 m.

Distribution. From Australia to Japan ( Saito et al., 2017) and now to Korea.

Remarks. Heretofore, Stenopus hispidus (Oliver, 1811) was the only reported stenopodid species in Korea ( Lee et al., 2015), thus, Odontozona arbur Saito, Okuno and Anker, 2017 could be the second species in the family. They are similar to each other by having spinulated carapace and short and biunguiculated dactyli of the fourth and fifth pereopods. However, they are easily distinguishable by the dorsal surface of abdominal somites in O. arbur without spines. The present specimen of O. arbur is almost identical to the original description by Saito et al. (2017). However, it is slightly different from the carapace, telson, and carpus of the first pereopod. According to the original description and figures, telson with 6 spines on the medial part, and the carpus of the first pereopod unarmed, whereas, the present specimen has less spines of the carapace than the original description, 7 spines of the medial part of the telson and a spine on the distolateral margin in the carpus of the first pereopod. These differences seem to be attributable to the intraspecific variation, however, additional morphological researches is needed.

Figures

Fig. 1. Odontozona arbur Saito, Okuno and Anker, 2017, female (pocl 3.8 mm). A, Carapace, lateral view; B, Antennule, ventral view; C, Antennal scale, ventral view; D, Abdomianl somites, lateral view; E, Telson and right uropod, dorsal view; F, Left third maxilliped, lateral view; G, Right first pereopod, lateral view; H, Right second pereopod, lateral view; I, Right third pereopod, lateral view; J, Right fourth pereopod, lateral view; K, Right fifth pereopod, lateral view. Scale bars: 1 mm.