Decaphyllus brevis, Komai & Rahayu, 2013
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publication ID |
https://doi.org/ 10.5281/zenodo.5352524 |
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publication LSID |
lsid:zoobank.org:pub:3EC76281-1ABA-4E72-BBE1-0BF811387484 |
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persistent identifier |
https://treatment.plazi.org/id/850B9A25-FFD5-FF9F-719B-FDF0FD229980 |
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Tatiana |
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scientific name |
Decaphyllus brevis |
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sp. nov. |
Decaphyllus brevis , new species
( Figs. 1–3 View Fig View Fig View Fig )
Material examined. — Holotype: ovigerous female (sl 1.3 mm), PANGLAO 2004, stn T4 , Bolod , Panglao Islands, 09°33.0'N, 123°48.5'E, 82 m, many sponges, 1 Jun.2004, trawl, NMCR 39086 GoogleMaps . Paratype: 1 ovigerous female (sl 1.6 mm), PANGLAO 2004, stn P1, Maribohoc Bay , Panglao Islands, 09°36.1'N, 123°45.0'E, 90–200 m, 30 May 2004, tangle nets from local fishermen, ZRC 2013.0678 View Materials GoogleMaps .
Description. — Ten pairs of biserial phyllobranchiae (no pleurobranchs).Arthrobranchs above base of third maxilliped very small, each gill bilobed.
Shield ( Fig. 1A View Fig ) approximately as long as wide; anterior margin between rostral region and lateral projection very slightly concave; anterolateral margins sloping; posterior margin roundly truncate; dorsal surface with poorly calcified area along midline, with few short setae laterally. Rostrum obsolete. Lateral projections moderately developed, each with terminal spinule.
Ocular peduncle ( Fig. 1A View Fig ) about 0.8 length of shield, faintly constricted at midlength; dorsal surface with mesial row of tufts of moderately short to long setae directed mesially, few median and lateral setae, and prominent tuft of long setae at base of cornea; cornea not dilated, its width about 0.3 of length of ocular peduncle; basal width subequal to corneal width. Ocular acicle tapering distally into acute spine, mesial margin with few long setae; separated basally by width of 1 acicle. Interocular lobe visible in dorsal view, anteriorly flat.
Antennular peduncle ( Fig. 1A View Fig ) overreaching distal corneal margin by about half length of ultimate segment. Basal segment with prominent spine on lateral margin of statocyst lobe, without ventromesial subdistal spine. Penultimate and ultimate segments unarmed, almost glabrous except for 2 thin short setae at dorsomesial distal angle of ultimate segment.
Antennal peduncle ( Fig. 1A View Fig ) reaching to base of cornea of ocular peduncle. Fifth and fourth segments with few setae. Third segment with prominent spine on ventromesial distal margin. Second segment with dorsolateral distal angle strongly produced, terminating in bifid spine (lateral spine distinctly subterminal), dorsomesial distal angle with tiny spine. First segment with 1 small spine on ventrodistal margin; lateral surface unarmed. Antennal acicle slightly falling short
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. gill gill 1968, posterior posterior Laurent,, Saint lamellae, bud-like bud-like bud-like, de two bud-like, lamellae simple, simple Decaphyllus of consisting non-lamellate of, few but, with, anterior gill non-lamellate,, gill anterior species small, small small small in very very lamellate very very small very small very maxilliped each, present,, both each, each,, both, each on arthrobranchs third Condition absent completely two arthrobranchs present absent completely arthrobranchs two present one only arthrobranch present arthrobranch two two present arthrobranchs two arthrobranchs present present two arthrobranchs two arthrobranchs present of development Comparison of barunajaya species, new species, new deliquus species new, new species, proprius spinicornis new species,. Table 1 Species. D brevis D. D. janquai . D. litoralis D maci D. D. D similis . D.. tenuis D or reaching distal margin of fifth peduncular segment or of corneal base or reaching to corneal base, terminating in small spine; mesial surface almost glabrous; lateral margin unarmed. Antennal flagellum with 2–4 short setae on distal margin of each article.
Third maxilliped ( Fig. 1B View Fig ) with merus armed with strong dorsodistal spine; crista dentata on ischium consisting of 2 widely separated triangular teeth; basis unarmed on mesial face. Exopod long, reaching to distal margin of carpus.
Chelipeds ( Fig. 2 View Fig ) subequal in length; right only slightly longer, but appreciably stronger. Right cheliped ( Fig. 2A–D View Fig ) with chela elongate subovate in dorsal view, about 2.2 times longer than wide. Dactylus ( Fig. 2C View Fig ) set at slightly oblique angle to palm, slightly shorter than palm; dorsal surface with 3 or 4 tiny spines or tubercles proximally; all surfaces with scattered moderately short to long setae, particularly numerous on mesial surface; cutting edge with row of small, blunt calcareous teeth, terminating in tiny corneous claw. Palm ( Fig. 2A–C View Fig ) subequal in length to carpus; dorsomesial margin with row of small spines, dorsal midline with row of small spines or tubercles decreasing in size distally, dorsolateral margin not delimited and without spines, dorsal surface lateral to midline with some small spines or tubercles near base of fixed finger; lateral surface with scattered short to moderately short setae; mesial surface also with scattered moderately short setae; ventral surface convex, smooth, with sparse setae. Fixed finger with row of blunt calcareous teeth on cutting edge, terminating in tiny calcareous claw. Carpus ( Fig. 2A–C View Fig ) subequal in length to merus, moderately widened distally, about 1.7 times longer than wide; dorsomesial margin with row of 4 small to moderately large spines, dorsolateral surface with row of 3 moderately large spines; all surfaces with scattered short to long setae, subdistal transverse row of setae particularly prominent; ventrolateral distal angle and ventromesial angle each with 1 tiny spine. Merus ( Fig. 2A, B, D View Fig ) with 1 small spine on dorsodistal margin mesially; dorsal surface with sparse setae; ventrolateral margin with 1 moderately small spine subdistally; mesial surface with 1 small spiniform tubercle proximoventrally, ventromesial margin with 2 small spines, proximal spine directed mesially; ventral surface with 1 spine medially. Ischium ( Fig. 2D View Fig ) with 1 small spine on ventromesial margin distal to midlength; lateral surface with 1 spinule subdistally.
Left cheliped ( Fig. 2E–H View Fig ) without hiatus between dactylus and fixed finger. Dactylus ( Fig. 2E, G View Fig ) about 1.1 times longer than palm, with 1 minute tubercle on dorsal surface mesially and proximal to midlength, and with short to long setae, particularly numerous on mesial surface; cutting edge with row of small, blunt calcareous teeth, terminating in small corneous claw. Palm ( Fig. 2E, G View Fig ) about 0.8 length of carpus; dorsomesial margin with row of 5 minute spines, dorsal midline with 2 small proximal spines and row of 4 minute tubercles, dorsolateral margin with irregular row of minute tubercles or denticles extending onto fixed finger; all surfaces with scattered short to long setae. Fixed finger with row of tiny calcareous teeth on cutting edge, terminating in small corneous claw. Carpus ( Fig. 2E–G View Fig ) about 2.6 times longer than wide, moderately widened distally; dorsolateral margin with 3 small spines in distal half, dorsomesial margin with 4 spines (distal second spine largest); ventrolateral distal angle with 1 minute spine, ventromesial distal angle unarmed; all surfaces with scattered setae. Merus ( Fig. 2E, F, H View Fig ) with sparse setae on dorsal surface; dorsodistal margin with 1 small spine; ventrolateral margin with 1 small subdistal spine; mesial surface with 1 prominent, anteriorly curved spine proximoventrally, ventromesial margin with 3 spines, second spine directed posteriorly, others directed anteriorly; ventral surface unarmed, with scattered setae. Ischium ( Fig. 2H View Fig ) with 2 tiny, mesially directed spines on ventromesial margin; lateral surface unarmed.
Ambulatory legs ( Fig. 3 View Fig ) overreaching tip of right cheliped. Dactyli ( Fig. 3A, B, D View Fig ) 1.6–1.8 times longer than propodi, 11–12 times longer than broad, slightly curved ventrally; all surfaces unarmed, but with numerous setae, particularly longer on dorsal margins. Propodi unarmed, but with row of sparse short setae on dorsal and ventral margins and scattered very short setae on lateral and mesial faces (second, Fig. 3A View Fig ) or almost glabrous (third, Fig. 3D View Fig ). Carpi each with dorsodistal spine, and 2 additional small spines (second, Fig. 3C View Fig ) or 2 minute denticles (third, Fig. 3E View Fig ) located on proximal one-third of dorsal margin; dorsal and ventral surfaces with sparse setae. Meri ( Fig. 3A, C–E View Fig ) each with 2 small dorsal spines (distal spine located at distal 0.2 in second, distal 0.4 in third; proximal spine at proximal 0.2 in both second and third): dorsal and ventral margins with sparse long, distinctly plumose setae, latter with spinule distal to midlength (second) or unarmed (third). Ischium ( Fig. 3C, E View Fig ) with 1 small subdistal spine on ventral margin (second) or unarmed (third).
Fourth pereopods ( Fig. 1C View Fig ) with claw of dactylus entirely masked by tufts of short, dense setae; propodus with sparse setae on dorsal and ventral margins; no corneous scales apparently present. Fifth pereopods semichelate.
Female with unpaired left gonopore. Anterior lobe of thoracic sternite 6 (third pereopods, Fig. 1D View Fig ) subtrapezoidal, slightly skewed to left, bearing some moderately long setae anteriorly. Sternite of thoracic sternite 8 (fifth pereopods) in female ( Fig. 1E View Fig ) subcircular, with row of moderately short setae anteriorly.
Telson ( Fig. 1F View Fig ) with median cleft small, V-shaped; terminal margin with prominently produced, spinose left exterior angle separated from weakly developed, also spinose right exterior angle, otherwise unarmed; lateral margins not forming chitinous plate.
Male unknown.
Colouration. — In preservative. No distinct markings seen on body and appendages. Shield, chelipeds and ambulatory legs with iridescence.
Distribution. — Known only from off Panglao Island, 82 m.
Remarks. — Although only two ovigerous females are available, this new species is safely assigned to the genus Decaphyllus by unarmed but setose dactyli of the ambulatory legs, the non-chelate fourth pereopod, and the entire thoracic sternite 8.
Decaphyllus brevis , new species, resembles D. litoralis , new species, described below. Shared characters include: ocular peduncle relatively short, 0.8–0.9 times as long as shield, with cornea showing no dilation; antennal acicle not overreaching distal margin of fifth peduncular segment; dactylus of right cheliped with at least a few tiny spines or tubercles on dorsal surface; dorsal surface of palm of right cheliped lateral to midline without scattered spines or tubercles; and merus of right cheliped bearing mid-ventral spine. The present new species can be differentiated from D. litoralis by the following characters. On the third maxilliped, there are two arthrobranch gills, each bilobed in D. brevis , whereas there is only a single, simple, bud-like arthrobranch gill in D. litoralis . The antennal acicle falls short of the distal margin of the fifth segment of the antennal peduncle in D. brevis , rather than slightly overreaching it in D. litoralis . The distal-sided dorsal spine on the merus of the second pereopod is located more distally in D. brevis than in D. litoralis (about distal 0.3 versus about midlength). The merus of the second pereopod is also armed with a median spinule on the ventral margin in D. brevis , while unarmed in D. litoralis . The terminal margin of the telson is devoid of spinules between the exterior angles in D. brevis , rather than armed with spinules in D. litoralis . Finally, in D. brevis , iridescent sheen is seen on the shield, chelipeds and ambulatory legs, while it is absent in D. litoralis .
The present new species is also somewhat similar to D. spinicornis and D. tenuis , new species. Decaphyllus spinicornis is immediately distinguished from D. brevis by the presence of a prominent spine on the mesial surface of the basal segment of the antennular peduncle and the relatively longer antennal acicle (Komai & Takeda, 2006). In D. brevis , the mesial surface of the ultimate segment of the antennular peduncle is unarmed; the antennal acicle slightly falls short of the distal margin of the fifth peduncular segment, rather than overreaching in D. spinicornis . Decaphyllus tenuis is also readily distinguished from D. brevis by the more pronounced rostral lobe and the more slender right chela (about 3.0 times as long as wide versus 2.2 times), which bears scattered small spines or tubercles on the dorsal surface lateral to the midline.
Etymology. — From the Latin “ brevis ” (= short), in reference to the relatively short antennal acicle of this new species.
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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