Pseudharpinia ovata, Senna, 2010

Senna, André R., 2010, A new genus and five new species of Phoxocephalidae (Crustacea: Amphipoda) from the south-east Brazilian deep sea, Journal of Natural History 44 (33 - 34), pp. 2075-2118 : 2108-2117

Pseudharpinia ovata sp. nov.

( Figures 17–20 )

Material examined

Holotype: 1 female, 5.4 mm, Petrobras , Campos Basin, N / Rb Astro Garoupa, boxcorer, #38, 22°41′08″ S, 40°14′06″ W, 1100 m depth, 15 May 2003, MNRJ 19204 . Paratype: one female, 3.7 mm, Petrobras , Campos Basin, N / Rb Astro Garoupa, box-corer, #50A, 22°02′31″ S, 39°52′13″ W, 1050 m depth, 29 June 2003, MNRJ 21029 .

Etymology

The species name is an adjective and refers to the ovate shape of the uropod 3 rami. Diagnosis

Antenna 2, article 4, with a facial row of six stout setae, ventral margin with three long simple setae, four long plumose setae, and three lateral stout setae. Mandible, incisors multicuspidate. Maxilla 1, inner plate small, subtriangular, with one long simple apical seta. Maxilla 2, inner plate inner margin setulose, with one apical plumose seta; outer plate, inner and outer margins without setules. Gnathopods 1 and 2, palm acute, sinuous, about 0.7 times as long as posterior margin, defined by a blunt projection with a lateral stout seta; gnathopod 2 slightly stronger than gnathopod 1. Pereopod 6, coxa twice as wide as long; basis anterior margin convex, with plumose setae, posterior margin slightly concave; dactyl, about half as long as propodus. Pereopod 7, basis, posterior margin serrate, spines blunt, almost rounded. Epimeral plate 3, ventral margin without setae, posterior margin with three small slender setae. Uropod 2, peduncle, dorsal margin with four stout setae distally; outer ramus, dorsal margin with two stout setae, ventral margin with three slender setae distally. Uropod 3, inner ramus short, ovate, subequal in length to peduncle, bearing a single long slender seta apically; outer ramus article 1 ovate, without setae, article 2 reduced, rounded, bearing two long apical slender setae. Telson, apical margin slightly rounded to subacute, with one subapical small slender seta and three dorsolateral setae in each lobe.

Description

Head, rostrum well developed, unconstricted; dorsal keel present; eyes absent. Antenna 1, article 1 dorsal margin without setules, anterodorsal corner with two small slender setae, anteroventral corner with five small plumose setae, 1.2 times longer than broad; article 2 about as long as wide, anterodorsal corner without setae, ventral margin with four long plumose setae; article 3 shortened, about 0.7 times as long as wide, with two ventral slender setae; flagellum with four articulations; accessory flagellum with seven articulations. Antenna 2, article 1 strongly ensiform; article 3, anterodorsal corner with one slender seta, ventral margin with one plumose slender setae; article 4, with a facial row of six stout setae, ventral margin with three long simple setae, four long plumose setae, and three lateral stout setae; article 5 slender, ventral margin with four stout setae; flagellum with five articulations. Mandible, incisors with multicuspidate apical margin; molar not triturative, with two apical slender setae; accessory setal row with six setae, hump of palp small; right lacinia mobilis apically multi-cuspidate, left one with three apical cusps; palp with three articulations, article 1 about twice as long as broad, article 2 elongated, about 3.8 times longer than broad, 1.2 times longer than article 3, ventral margin with one mid-length plumose seta, ventroapical corner with one plumose seta, article 3 about six times longer than broad, apically setose. Maxilla 1, inner plate small, subtriangular, with one long simple apical seta; outer plate, with two rows of stout setae; palp bi-articulated, article 2 apically setose, with facial setules near the inner margin. Maxilla 2, inner plate slightly shorter than outer plate, with four small apical simple setae, inner margin setulose, with one apical plumose seta; outer plate, apical margin with seven slender setae, inner and outer margins without setules. Maxilliped, inner plate small, subrectangular, with two plumose setae and two small simple setae; outer plate well developed, apical margin armed with curved simple setae; palp with four articulations, article 2 about twice as long as broad, about 1.5 times longer than article 3, inner margin armed with simple setae, article 3, inner margin with two slender setae, lateroapical margin with three slender setae; article 4 slender, slightly elongated, without setae, outer margin with one single small setule, apical nail present.

Gnathopod 1 small, coxa expanded anteriorly, anterior and posterior margins slightly divergent, anterior margin straight, without setae, posterior margin slightly convex, without setae, ventral margin with eight plumose setae; basis, about 2.3 times longer than broad, posterior margin without setae, posteroventral corner with one plumose seta; merus, with one simple lateral seta, posterior margin without setae; carpus free, with weak eusirid attachment, about 1.5 times longer than broad; propodus ovatorectangular, weakly elongated, about 2.4 times longer than broad, anterior margin without setae, anterodistal corner with three long slender setae, palm acute, sinuous, about 0.7 times as long as posterior margin, defined by a blunt projection with a lateral stout seta; dactyl curved, reaching the palmar corner, outer margin with one proximal and one subapical small setule. Gnathopod 2 slightly larger than gnathopod 1, coxa subrectangular, about 1.5 times longer than broad, anterior margin almost straight, without setae, posterior margin straight, without setae, ventral margin with four plumose setae, increasing in length posteriorly; basis, about three times longer than broad, posterior margin with two long slender setae, posteroventral corner with one plumose seta; merus, posterodistal corner produced, posterior margin with one slender seta proximally, besides three simple setae and three plumose setae distally; carpus short, free, with weak eusirid attachment; propodus ovatorectangular, weakly elongated, about 1.9 times longer than broad, anterior margin without setae, anterodistal corner with two long slender setae, palm acute, sinuous, about 0.7 times as long as posterior margin, defined by a strong projection with a lateral stout seta; dactyl curved, reaching the palmar corner, outer margin with one small setule. Pereopod 3, coxa subrectangular, about 1.4 times longer than broad, anterior margin almost straight, posterior margin without setae, ventral margin with four posteroventral plumose setae, increasing in length posteriorly; basis, about 2.5 times longer than broad, anterior margin without setae, posterior margin with one long plumose seta, posteroventral corner with four long plumose setae; ischium with three plumose setae posterodistally; merus, carpus and propodus, length ratio 5: 2: 2; merus, posterior margin with four rows of plumose setae (2-1-2-3); carpus, posterior margin with five long stout setae and three lateral slender setae; propodus, posterior margin with one slender seta distally; dactyl slightly shorter than propodus. Pereopod 4, coxa about 1.2 times wider than long, anterior margin almost straight, posterior margin broadly rounded, ventral margin with three anteroventral small slender setae, posterodorsal margin excavate; basis, about 2.5 times longer than broad, anterior margin without setae, posterior margin with one long slender seta, posteroventral corner with two plumose setae; merus, carpus and propodus, length ratio 22: 7: 9; merus, posterior margin with long plumose setae; carpus, posterior margin with five long stout setae and one lateral slender seta; propodus, posteroventral corner with two slender setae; dactyl about 0.7 times as long as propodus. Pereopod 5, coxa bilobate, anteroventral lobe with two plumose setae and one setule; basis slender, about 2.2 times longer than broad, anteroventral corner with two slender setae, posterior margin with one long plumose seta, posteroventral corner with three plumose setae; ischium with one plumose seta posterodistally; merus, carpus and propodus, length ratio 11: 12: 11; merus, anterior margin with two slender setae, anteroventral corner with one slender seta, posterior margin with three rows of plumose setae (1-2-3); carpus, anterior margin with three rows of slender setae (1-1-3), posterior margin with three rows of plumose setae (1-3-4); propodus, anterior margin with three rows of slender setae (1-2-3), posterior margin with three distal slender setae; dactyl about 0.7 times as long as propodus. Pereopod 6, coxa small, twice as wide as long, slightly expanded posteroventrally, with a minute setule posteroventrally; basis without posterior expansion, about 1.5 times longer than broad, anterior margin convex, with plumose setae continuously to apex, posterior margin slightly concave, with two setules proximally; merus, carpus and propodus, length ratio 6: 5: 5; merus, about 1.8 times longer than broad, anterior margin with one slender seta, anteroventral corner with two setae; posterior margin and posteroventral corner without setae; carpus, about 1.6 times longer than broad, anterior margin with three rows of stout setae (2-1-3), posteroventral corner with two short stout setae; propodus thin, about 3.3 times longer than broad, anterior margin with two long slender setae and one long stout seta, apical margin with three slender setae, posterior margin without setae; dactyl slender, about half as long as propodus. Pereopod 7, coxa slightly expanded posteroventrally; basis, strongly expanded posteriorly, anterior margin with one small and five long plumose setae distally, posterior margin serrate, spines blunt, almost rounded, with one small slender seta on each notch; ischium enlarged, anterior margin with one small and three long plumose setae; merus, carpus and propodus, length ratio 9: 8: 6; merus, about 1.1 times longer than broad, anteroventral and posteroventral corners with one small and one long slender seta each one; carpus, about 1.5 times longer than broad, anterior margin with two slender setae, posteroventral corner with one long slender seta; propodus, about twice as long as broad, anteroventral and posteroventral corners with one slender seta each one; dactyl thin, about 1.4 times longer than propodus.

Epimeral plate 3, ventral margin without setae, posterior margin with three small slender setae, posteroventral corner produced in a curved upwards acute process. Urosomite 3 smooth. Uropod 1, peduncle elongated, about 2.6 times longer than broad, with two lateral distal setae, dorsoapical corner with two slender setae; rami slightly shorter than peduncle, outer ramus dorsal margin with three stout setae. Uropod 2, peduncle about twice as long as broad, dorsal margin with four stout setae distally; inner ramus subequal in length to peduncle, without setae; outer ramus, slightly longer than inner ramus, dorsal margin with two stout setae, ventral margin with three slender setae distally. Uropod 3, peduncle short, about as long as broad, dorsoapical corner with two small slender setae, ventroapical corner with one stout seta; inner ramus short, ovate, subequal in length to peduncle, about twice as long as broad, bearing a single long slender seta apically; outer ramus bi-articulated, about 1.3 times longer than inner ramus, article 1 slightly longer than inner ramus, ovate, without setae, article 2 reduced, rounded, bearing two long apical slender seta. Telson slightly wider than long, deeply cleft, about 75% of its length, apical margin slightly rounded to subacute, with one subapical small slender seta and three dorsolateral setae on each lobe.

Remarks

Pseudharpinia ovata sp. nov. is easily distinguished from all other species of the genus by maxilla 1, inner plate small, subtriangular, with only one long slender apical seta; pereopod 6, anterior margin with long plumose setae continuously to apex; pereopod 7, basis with posterior margin weakly serrate, with small slender setae; epimeral plate 3, ventral margin without setae and posterior margin with three small slender setae above the curved upwards process; and uropod 3, inner ramus and outer ramus article 1 suboval, article 2 short and rounded.

Besides those features cited above, Pseudharpinia ovata sp. nov. has some characters unlike those observed in P. berardo sp. nov. The dorsal margin of antenna 1 article 1 is without setules or setae, in contrast to what is observed in P. berardo sp. nov.; article 4 of the peduncle of antenna 2 of P. ovata sp. nov. does not have a papose seta at the end of the the facial row unlike P. berardo sp. nov.; maxilla 2 in P. ovata sp. nov. has only the inner margin of the inner plate setulose, whereas in P. berardo sp. nov. the inner and outer margins of the outer plate are also setulose; mandible, palp article 1 in P. ovata sp. nov. is about twice as long as broad, dissimilar to P. berardo sp. nov. with palp article 1 about as long as wide; the posterior margin of pereopod 6 basis in P. ovata sp. nov. is slightly concave, in contrast to the straight posterior margin of P. berardo sp. nov.; the merus, carpus and propodus in P. ovata sp. nov. are also more robust than in P. berardo sp. nov.

Geographic distribution

Known only from the type locality, Campos Basin , off Rio de Janeiro State coast .

Bathymetric range

Collected from 1050 m to 1100 m depth.

Identification key to species of Phoxocephalidae from Brazilian waters

1. Rostrum constricted or not. Pereopod 5, basis posteriorly expanded. Urosomite 3, dorsal hook present or absent............................... 2 Rostrum unconstricted. Perepod 5, basis posteriorly not expanded. Urosomite 3, dorsal hook absent...................................... 6

2. Rostrum constricted. Antenna 1, peduncle article 2 elongated. Pereopod 5, merus and carpus enlarged. Urosomite 3, dorsal hook present........................................................... Microphoxus (3) Rostrum constricted or not. Antenna 1, peduncle article 2 shortened. Pereopod 5, merus and carpus not enlarged. Urosomite 3, dorsal hook absent...............................................................11

3. Pereopod 7 basis, posteroventral lobe truncate...................... 4 Pereopod 7 basis, posteroventral lobe not truncate................... 5

4. Pereopod 7 basis, posteroventral lobe reaching the end of ischium; posterior margin distally serrate. Uropods 1–2, rami shorter than peduncle........................................... M. breviramus Bustamante, 2002 Pereopod 7 basis, posteroventral lobe reaching the end of merus; posterior margin medially serrate. Uropods 1–2, rami subequal in length to peduncle................................. M. cornutus (Schellenberg, 1931)

5. Pereopod 7 basis, posteroventral lobe reaching the end of carpus; posterior margin proximally and medially serrate. Uropods 1–2, apicolateral corner of peduncle without comb.................. M. moraesi Bustamante, 2002 Pereopod 7 basis, posteroventral lobe reaching the end of merus; posterior margin medially serrate. Uropods 1–2, apicolateral corner of peduncle with comb............................... M. uroserratus Bustamante, 2002

6. Antenna 2, article 1 not ensiform. Pereopod 7, ischium not enlarged..... 7 Antenna 2, article 1 strongly ensiform. Pereopod 7, ischium enlarged.... 8

7. Head, without lateral notches; anteroventral spine present. Pereopod 5, merus and carpus more than three times longer than broad. Urosomite 1, dorsal carina absent. Epimeral plate 3, posteroventral corner produced into a small acute upwards process....... Harpiniopsis galera Barnard JL, 1960 Head, with lateral notches; anteroventral spine absent. Pereopod 5, merus and carpus less than 1.5 times longer than broad. Urosomite 1, dorsal carina present. Epimeral plate 3, posteroventral corner rounded...................................................... Coxophoxus alonso sp. nov.

8. Pereopod 7 basis, posterior margin with broadly rounded spines........ 9 Pereopod 7 basis, posterior margin with strongly acute spines..........10

9. Eyes present. Pereopod 7 basis, posteroventral lobe reaching the end of merus. Pleon dorsally setose. Epimeral plate 3, posteroventral corner produced into a small subacute process. Uropod 3, rami elongated; outer ramus, article 1 setose................. Heterophoxus videns Barnard KH, 1930 Eyes absent. Pereopod 7 basis, posteroventral lobe reaching the end of ischium. Pleon dorsally without setae. Epimeral plate 3, posteroventral corner produced into a strong acute upwards process. Uropod 3, rami ovate; outer ramus, article 1 without setae.......... Pseudharpinia ovata sp. nov.

10. Uropod 3, outer ramus 1.5 times longer than peduncle; article 2 reduced......................................... Pseudharpinia affinis dentata Uropod 3, outer ramus twice as long as peduncle; article 2 elongated................................................ .. Pseudharpinia berardo sp. nov.

11. Head, rostrum constricted, sharp and deflexed; eyes absent. Pereopod 7 basis, posterior margin sinuous........... Leptophoxoides marina sp. nov. Head, rostrum unconstricted, not sharp and not deflexed; eyes present. Pereopod 7 basis, posterior margin serrate.............................. 12

12. Mandible, molar not triturative. Maxilla 1, palp bi-articulated. Pereopod 7 basis, posterior margin medially serrate.... Bathybirubius margaretae sp. nov. Mandible, molar strongly triturative. Maxilla 1, palp uni-articulated. Pereopod 7 basis, posterior margin proximally and medially serrate....................................... Phoxocephalus homilis Barnard JL, 1960

Figures

Figure 17. Pseudharpinia ovata sp. nov.: female, 5.4 mm, holotype, Campos Basin, 22°41′08″ S, 40°14′06″ W, 1100 m depth, 15 May 2003, MNRJ 19204. Scale bars: 1.0 mm for Hb; 0.5 mm for Hd.

Figure 18. Pseudharpinia ovata sp. nov.: female, 5.4 mm, holotype, Campos Basin, 22°41′08″ S, 40°14′06″ W, 1100 m depth, 15 May 2003, MNRJ 19204. Scale bars: 0.1 mm.

Figure 19. Pseudharpinia ovata sp. nov.: female, 5.4 mm, holotype, Campos Basin, 22°41′08″ S, 40°14′06″ W, 1100 m depth, 15 May 2003, MNRJ 19204. Scale bars: 0.1 mm.

Figure 20. Pseudharpinia ovata sp. nov.: female, 5.4 mm, holotype, Campos Basin, 22°41′08″ S, 40°14′06″ W, 1100 m depth, 15 May 2003, MNRJ 19204. Scale bars: 0.1 mm.