Barathricola thermophilus, Ivanenko, Viatcheslav N., Lee, Jimin, Chang, Cheon Young & Kim, Il-Hoi, 2019
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publication ID |
https://dx.doi.org/10.3897/zookeys.865.35827 |
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publication LSID |
lsid:zoobank.org:pub:9A0189C5-540B-4BF9-87C2-24EB5B74D5A1 |
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persistent identifier |
https://treatment.plazi.org/id/3AE79CB6-053D-406B-ADA5-69477A4D462A |
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taxon LSID |
lsid:zoobank.org:act:3AE79CB6-053D-406B-ADA5-69477A4D462A |
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treatment provided by |
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scientific name |
Barathricola thermophilus |
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sp. nov. |
Barathricola thermophilus sp. nov. Figs 1 View Figure 1 , 2 View Figure 2 , 3 View Figure 3
Type locality.
The hydrothermal vent field of OVF (11°24'52.97"S, 66°25'25.48"E) on the Central Indian Ridge in the Indian Ocean; sediments at 2022 m in depth.
Type material.
Holotype (♀, MABIK CR00244723) and paratypes (6 ♀♀, 6 ♂♂, MABIK CR00244724) have been deposited in the MABIK. Dissected paratypes (2 ♀♀, 1 ♂) are retained in the collection of the last author. All type specimens collected on 23 June 2018 from the type locality.
Description of female.
Body ( Fig. 1A View Figure 1 ) slender. Length of dissected and described specimen 776 μm. Other three measured specimens 700, 710, and 715 μm, respectively. Prosome nearly oval, 400 μm long, slightly longer than urosome, consisting of cephalosome and four pedigerous somites. Greatest width of prosome 273 μm across cephalosome. Cephalosome with angular posterolateral corners. First to third pedigerous somites almost equal in length. Fourth pedigerous somite distinctly shorter and narrower than the third. Urosome ( Fig. 1B View Figure 1 ) slender, 5-segmented. Fifth pedigerous somite 38 × 74 μm, broadened distally, with angular posterolateral corners. Genital double-somite 109 × 70 μm, 1.56 times as long as wide, gradually narrowing posteriorly; genital aperture located dorsolaterally at 38% region of double-somite length. Three free abdominal somites 40 × 47, 30 × 42, and 50 × 37 μm, respectively. Anal somite with large anal region and minute spinules along ventrodistal margin. Caudal ramus ( Fig. 1C View Figure 1 ) 116 × 13 μm, 8.92 times as long as wide, more than twice as long as anal somite, armed with six setae and ornamented with row of spinules along ventrodistal margin; outer lateral seta located at 39% region of ramus length; spermatophore ( Fig. 1D View Figure 1 ) attached to female 60 × 27 μm, with thick wall.
Rostrum ( Fig. 1E View Figure 1 ) triangular, with thin-walled lobate distal apex. Antennule ( Fig. 1F View Figure 1 ) 225 μm long, longer than cephalosome, and 14-segmented. Eleventh segment the longest. Armature formula 2-5-4-7-6-(2 + aesthetasc)-0-1-0-1-(2 + aesthetasc)-2-(2 + aesthetasc)-(6 + aesthetasc). Second and third segments each with a trace of one subdivision, and fourth segment with three subdivisions. First segment with two rows of fine spinules. Most of setae naked, except several feebly pinnate ones of proximal two segments. Aesthetascs broad, constricted at region slightly distal to middle, and attenuated distally.
Antenna ( Fig. 1G View Figure 1 ) 4-segmented, consisting of basis and 3-segmented endopod. Basis unarmed, ornamented with several rows of minute spinules. First endopodal segment 36 × 17 μm, with one seta on inner margin and minute spinules proximally and on outer margin. Second endopodal segment narrow proximally and gradually broadened distally, 30 × 18 μm, armed with five setae (three distal and two smaller subdistal) and ornamented with row of minute setules on outer side. Third endopodal segment 23 × 14 μm, armed with seven unequal setae distally, and ornamented with setules on outer side.
Labrum weak, easily destroyed. Mandible ( Fig. 1H View Figure 1 ) consisting of coxa, basis, exopod, and endopod. Coxa with setules on outer margin; cutting margin of gnathobase with six acutely pointed teeth, two thin proximal setae, three setules between distal second and third teeth, and one small, transparent digitiform process bearing fine spinules distally between distal first and second teeth. Basis elongate, 42 × 9 μm, bearing five or six setules subdistally. Exopod small, indistinctly 3-segmented, armed only with two setae on third segment, outer one of these setae sparsely pinnate and slightly longer than inner one. Endopod 2-segmented, armed with two and four setae on first and second segments, respectively, all six setae sparsely pinnate; first segment with several setules on medial margin.
Maxillule ( Fig. 1I View Figure 1 ) with eight setae on praecoxal arthrite; second distal seta spiniform. Coxal endite absent. Epipodite with two unequal setae. Basis with four setae, three proximal and one distal. Exopod with four large setae distally; setae becoming longer from outer to inner margin. Endopod shorter than exopod, armed with five setae, one on medial margin, and four distally.
Maxilla ( Fig. 2A View Figure 2 ) stout, 5-segmented, consisting of syncoxa, basis, and 3-segmented endopod. Syncoxa armed with 11 setae, grouped as four, one, three, and three on first to fourth endites, respectively; third and fourth endites ornamented with two spinules at distal region. Basis armed with three unequal setae (one large, proximally unarticulated, spiniform, one long, and one small setae) and ornamented with one spinule. First endopodal segment with four setae (two proximal and two distal). Second endopodal segment with two long setae; third endopodal segment small, with four setae (one long and three shorter).
Maxilliped ( Fig. 2B View Figure 2 ) slender, 7-segmented, consisting of syncoxa, basis, and 5-segmented endopod. Syncoxa with several scattered rows of minute setules, and armed with three setae, proximal one small and naked. Basis with two setae and rather long setules on medial margin. Endopod armed with one, one, one, one, and three setae on first to fifth segments, respectively; middle seta on terminal segment naked, much longer than other setae, longer than basis and endopod combined. Articulation incomplete between third and fourth endopodal segments.
Legs 1-4 ( Figs 2 C–E View Figure 2 ; 3A View Figure 3 ) with 3-segmented exopod and endopod, lacking inner seta on first exopodal segment; third exopodal segment distinctly broader than proximal segments. All intercoxal sclerites smooth without spinule/setule array along distal margin and on both anterior and posterior surfaces. Endopods of legs 1-3 shorter than exopod, but that of leg 4 distinctly longer than exopod. Leg 1 ( Fig. 2C View Figure 2 ) basis with seven thick setules on inner margin; inner distal spine large, 48 μm long, extending to middle of third endopodal segment, spinulose along both margins. Leg 2 ( Fig. 2D View Figure 2 ) with inner coxal seta characteristically bent at proximal quarter; outer seta on basis shorter than those of legs 1, 3 and 4. Inner distal corner of basis of legs 2-4 with pointed dentiform process. Leg 3 ( Fig. 2E View Figure 2 ) with two distal spines on third endopodal segment (outer spine ca. half as long as inner spine). Leg 4 ( Fig. 3A View Figure 3 ), third endopodal segment elongate, 3.6 times as long as wide; inner distal seta on second endopodal segment and two inner and one outer setae on third endopodal segment transformed to spines. Armature formula for legs 1-4 as in Table 1.
Leg 5 ( Fig. 3B View Figure 3 ) 3-segmented, consisting of coxa, basis and exopod; intercoxal sclerite small, narrow, with pointed outer distal corners and slightly concave distal margin. Coxa quadrate, unarmed, not articulated from somite. Basis also quadrate, armed with one pinnate seta outer distally. Exopod 54 × 24 μm, 2.25 times as long as wide, armed with three spines (two distal and one outer) and one pinnate seta; medial margin spinulose and outer margin setulose.
Leg 6 ( Fig. 3C View Figure 3 ) represented by one spinule and one naked seta on genital operculum.
Description of male.
Body ( Fig. 3D View Figure 3 ) much narrower than that of female, 582 μm long. Prosome 314 × 153 μm, approximately twice as long as wide. First pedigerous somite slightly narrower than cephalosome and second pedigerous somite. Urosome 6-segmented. Fifth pedigerous somite narrower than genital somite. Genital somite ( Fig. 3E View Figure 3 ) 86 × 72 μm, longer than wide, with well-developed genital operculum. Four abdominal somites 25 × 40, 23 × 34, 20 × 31, and 30 × 28 μm, respectively. Caudal ramus 6.1 times as long as wide (61 × 10 μm); arrangement and locations of caudal setae as in female.
Rostrum as in female. Antennule ( Fig. 3F View Figure 3 ) 17-segmented; armature formula (2 + aesthetasc)-(5 + aesthetasc)-4-2-(2 + aesthetasc)-2-2-2-2(2 + aesthetasc)-(1 + spine)-(2 + aesthetasc)-2-[3 + aesthetasc (or 2+aesthetasc)]-[0 (or 1)]-(1 + aesthetasc)-(9 + 2 aesthetascs); eleventh segment with short posterior margin and much longer anterior margin, spine on this segment slender. Antenna as in female.
Mandible and other mouth appendages as in female.
Legs 1, 2, and 4 also as in female. Leg 3 sexually dimorphic; third endopodal segment ( Fig. 3G View Figure 3 ) bearing two spines, three setae, and distally two small specialized elements, one curved, non-articulating, spinule-like element and one straight, distally bifurcate articulating element.
Leg 5 as in female. Leg 6 ( Fig. 3E View Figure 3 ) represented by three naked setae on genital operculum, medial one smaller than other two.
Etymology.
The specific name thermophilus is a combination of Greek words therm (=heat) and phil (=loving), referring to the finding of the new species in a hydrothermal vent field.
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.