Bathytanais culterformis, Larsen & Heard, 2001
treatment provided by
Material examined. – Holotype: Nonovigerous female, P 61355 View Materials , body length 3.2 mm, Sta. SO 583 B2 , 19º56,7’S. 117 º53,6’E. Depth 41 m GoogleMaps . Paratypes: 2 nonovigerous females, P 61356 View Materials , same locality. Collected by staff on board RV “Soela” CSIRO 1983 GoogleMaps .
Other material: 12 Nonovigerous female, P 54288 View Materials , same locality GoogleMaps . 5 females, P 52195 View Materials , Sta. No. SO 383 B 2 , Lat. 19 º 56.4 'S, Long. 117 º 53.9 'E. Depth 44 m GoogleMaps . 1 female, P 52213 View Materials , Sta. No. SO 682 B 4 , Lat. 18 º 56.6 'S, Long. 118 º 44.9 'E. Depth 88 m GoogleMaps . 2 females, 1 manca, P 52211 View Materials , Sta. No. SO 683 B 1, Lat. 19 º03.0'S, Long . 119 º02.4'E. Depth 80 m GoogleMaps . 1 female, P 52198 View Materials Sta. No. SO 383 D 9, Lat. 19 º58.0'S, Long . 117 º 49.7 'E. Depth 43 m GoogleMaps . 7 females, P 52199 View Materials , Sta. No. SO 483 B 2, Lat. 19 º 56.7 'S, Long . 117 º 53.8 'E. Depth 42 m GoogleMaps . 1 female, P04972 View Materials . Sta. No. SO 383 B 7 , Lat. 19 º 30.8 'S, Long. 118 º 49.1 'E. Depth 38 m GoogleMaps . 1 female, P 52191 View Materials , SO 283 B 12, Lat. 19 º 56.9 ', Long . 117 º 53.7 'E. Depth 43m GoogleMaps . 1 female, P 52378 View Materials , Sta. No. SO 383 B 8 , Lat. 19 º 29.2 'S, Long. 118 º 52.5 'E. Depth 41 m. GoogleMaps
Diagnosis: Antenna with article 2 subquadrate, ventral margin bladelike, not serrated, slightly concave; distoventral margin subacute, with several setae. Article 3 of antenna not deeply recessed into article 2, with distodorsal and distoventral margins each produced into acute process. Labium with distal denticulated scales. Uropodal exopod almost as long as endopod.
Description (adult female)
Body ( Fig. 1 View FIGURE 1 A): Slender, subcylindrical, approximately 9 times longer than broad.
Cephalothorax ( Fig. 1 View FIGURE 1 B): Length near length of pereonite 1 and 2 together, width 0.75 length. Eye lobes acute.
Pereonites: Pereonite 1 wider than long. Pereonites 24 and 6, length subequal to width. Pereonite 5 longer than wide.
Pleon: Pleonites 15 similar in length and width, width approximately 4.0 length, all with 1 heavy articulated circumplumose seta. Pleotelson twice as long as last pleonite.
Antennule ( Fig. 1 View FIGURE 1 C): Longer than cephalothorax. Article 1 longer than rest of antennule, with several setules on outer margin. Article 2 longer than article 3, distal margin with 2 long simple setae and several setules. Article 3 length one quarter of article 4, with 1 simple and long setulated seta. Article 4 longer than article 2, with 1 simple and 5 distal setulated setae twice as long as antennule.
Antenna ( Fig. 1 View FIGURE 1 D): Length three quarters that of antennule. Article 1 lost. Article 2 with smooth ventral margin of the ventral expansion, distal ventral row of simple setae, 1 simple distal dorsal seta. Article 3 less than half as long as article 2, with dorsal spiniform seta and distal anteriorly directed ventral projection. Article 4 longer than article 3, with 1 long serrated distal seta on ventral margin and 3 short sensory setae. Article 5 as long as article 4, with 1 setulated distal seta of more than twice the length of the antennae. Article 6 minute with 3 setulose setae longer than antenna, 2 long and 1 short simple setae.
Mouthparts: Labrum ( Fig. 1 View FIGURE 1 E) flat, setose apex. Mandibles ( Figs. 1 View FIGURE 1 G & F) molar longer than incisor, left mandible with strongly defined lacina mobilis with several denticulations, incisor unidentate, right mandible with broad and bidentate incisor. Maxillule ( Fig. 1 View FIGURE 1 I) with 7 thick terminal setae and dorsal row of setae, palp shorter than endite. Maxilla ( Fig. 1 View FIGURE 1 I) ovoid. Labium ( Fig. 1 View FIGURE 1 H) with setules on anterolateral corners and distal denticulated scales. Maxilliped ( Fig. 1 View FIGURE 1 J) endites with 1 seta on inner corner and 2 medial short flat setae; palp article 1, outer margin longer than inner, smooth; article 2, inner margin longer than outer, with 3 setulated setae on inner distal margin, 1 short simple seta on outer distal margin; article 3, 4 setulated setae on inner margin; article 4 rectangular, inner margin with 5 setulated distal setae and several fine setules, outer margin with 1 setulated seta. Epignath ( Fig. 1 View FIGURE 1 K) with blunt finely setose apex.
Cheliped ( Fig. 1 View FIGURE 1 L): Basis smooth, twice as long as wide. Merus ovoid, with 1 simple seta medially on ventral margin. Carpus oval, longer than basis, with 2 simple setae on ventral margin, 1 distal seta on dorsal margin. Propodus with row of serrated dorsal setae by dactylus insertion. Fixed finger with strong tip, 2 simple setae on ventral margin, 3 on cutting edge and 1 at dactylus insertion. Dactyl narrow, with 1 seta on its dorsal margin.
Oostegites: originating from pereonites 14.
Pereopod 1 ( Fig. 2 View FIGURE 2 A): Longer than other pereopods. Coxa with simple seta. Basis as long as combined length of 3 succeeding articles, smooth. Ischium with 2 simple setae on ventral margin. Merus longer than carpus, with 2 simple distal setae on ventral margin. Carpus with 3 simple distal setae. Propodus twice as long as long as carpus, tapering distally, with 3 simple distal seta. Dactyl and terminal spine not fused, together longer than propodus.
Pereopod 2 ( Fig. 2 View FIGURE 2 B): Similar to pereopod 1 except: Basis as long as combined length of 4 succeeding articles. Merus expanding distally, with 2 simple distal setae on ventral margin, shorter than carpus. Carpus with 2 simple setae on ventral margin. Propodus with 3 simple distal seta.
Pereopod 3 ( Fig. 2 View FIGURE 2 C): Similar to pereopod 2 except: Coxa smooth. Merus with 1 simple distal seta. Carpus marginally longer than merus, with 1 distal simple seta. Propodus with 2 simple distal setae.
Pereopod 4 ( Fig. 2 View FIGURE 2 D): Basis stout and smooth. Ischium smooth. Merus shorter than carpus, with 2 short denticulated distal setae and denticulated scales. Carpus shorter than propodus, with denticulated scales, 1 simple and 2 short denticulated distal setae. Propodus with 1 sensory seta on dorsal margin, 1 long serrated and 2 spiniform setulose distal seta. Dactyl and terminal spine fused into a claw with setules.
Pereopod 5 ( Fig. 2 View FIGURE 2 E): As pereopod 4, except: Basis with 1 simple and 1 sensory setae on ventral margin. Ischium with 2 simple setae. Merus with few denticulated scales, 1 simple, 3 stout spiniform distal setae. Carpus as long as propodus with denticulated scales and 3 spiniform setulated distal setae.
Pereopod 6 ( Fig. 2 View FIGURE 2 F): As pereopod 5 except: Basis with 1 simple ventral seta. Merus as long as carpus, with 2 short stout distal setae. Propodus without sensory seta but with 3 stout setulated distal setae as long as dactylus.
Pleopods ( Fig. 2 View FIGURE 2 G): All 5 pairs similar. Protopod trapezoidal. Exopod armed with 19 plumose setae. Endopod, inner margin finely setose, with 15 plumose setae, 2 distal setae shorter and stouter than rest.
Uropods ( Fig. 2 View FIGURE 2 H): Protopod rectangular, with 1 simple seta. Endopod with incomplete fusion of articles, with 2 sensory setae midlength, 5 simple and 2 sensory distal setae. Exopod with 1 article, almost as long as endopod, with 1 simple seta midlength, 2 long simple distal setae.
Etymology: Named for the cleaverlike ventral edge on article 2 of the antennal peduncle (Latin: Culterformis = Cleaverlike).
Habitat: Specimens living in sandy bottom at 41m depth on the Northwest Australian shelf off Western Australia. Specimens were found in tubes consisting of sand grains and mucus.
Remarks: Bathytanais culterformis can be immediately distinguished from the other known members of the genus by the subquadrate shape of antennal article 2, which has bladelike, slightly concave, ventral margin produced into a relatively subacute distal process. The proximal ventral margin abruptly turns upward to the articulation with article 1, forming a subacute ventroproximal process. Bathytanais culterformis , B. bipennifer and B. bathybrotes (as described by Lang, 1972) are the only known species of the genus to have both a dorsal and a ventral distal process on antennal article 3, but those on the two first species are acute and those on the latter are rounded or lobate. The other four species lack a dorsal process. The smooth ventral margin on the antenna article 2 ventral processes separates B. culterformis from B. bipennifer , which has a serrated margin.
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.