Bonnierella laurensi, Souza-Filho & Serejo, 2014

Souza-Filho, Jesser F. & Serejo, Cristiana S., 2014, On the phylogeny of Ischyroceridae (Amphipoda, Senticaudata, Corophiida), with the description of a new genus and eight new species from deep-sea Brazilian waters, Zoological Journal of the Linnean Society 170 (1), pp. 34-85 : 53-59

BONNIERELLA LAURENSI SP. NOV. ( FIGS 11–13 )

Type material

Holotype: Male (3.1 mm; dissected and drawn), OCEANPROF II, BC-SUL, #84, Campos Basin , Rio de

Janeiro , Brazil, 22°26′41.4″S. 39°58′53.28″W, 1050 m, 20 June 2003, MNRJ 21231 .

Paratypes: Two females (one female dissected and drawn, 3.2 mm), OCEANPROF II, BC-SUL , # 84, Campos Basin , Rio de Janeiro, Brazil, 22°26′57.6″S, 39°58′53.28″W, 1050 m, 20 June 2003, MNRJ 21422 . Two males, OCEANPROF I, BC-SUL, # 71, Campos Basin , Rio de Janeiro, Brazil, 22°39′47.22″S, 40°04′14.22″W, 1350 m, 23 November 2002, MNRJ 21207 . One female, OCEANPROF II, BC-NORTE , # 44, Campos Basin , Rio de Janeiro, Brazil, 22°11′27″S, 39°54′45″W, 749 m, 1 July 2003, MNRJ 21210 . One female, OCEANPROF I, BC- SUL, #66, Campos Basin , Rio de Janeiro, Brazil, 22°45′37.2″S, 40°10′12″W, 1350 m, 22 November 2002, MNRJ 21485 .

Etymology

Bonnierella laurensi sp. nov. is named in honour of Dr Jerry Laurens Barnard (1928–1992), one of the most important amphipodologists in the last century, who made important contributions to the systematics of this genus.

Type locality

Campos Basin, Rio de Janeiro, Brazil.

Diagnosis

Maxilliped outer plate ovate, reaching more than half of palp article 2; palp 4-articulate, article 4 slightly shorter than article 3, with apical nail. Gnathopod 1 propodus triangular, setose, and longer than carpus, palm acute and crenulated; dactylus fitting palm. Gnathopod 2 carpus triangular and short; propodus massive, 2.6 × carpus length, palm shorter than posterior margin with two processes, first one proximal and triangular, dentate on anterior part, second one blunt, both separated by a deep U-shaped excavation followed by a concave crenulate portion, palmar corner defined by a well-developed acute process, facial margin with one pair of short and long robust setae, inner surface with two robust setae; dactylus stout with a spine about two-thirds its length. Pereopod 6, basis with posterior margin sinuous. Uropod 1 peduncle interamal process about onefifth of peduncle length; rami with one apical seta. Uropod 2 interamal process short and blunt. Uropod 3 peduncle 1.2 × outer ramus length; outer ramus with five subapical tiny spines. Telson triangular, longer than wide with two dorsal slender setae and three pairs of pappose setae, tip acute.

Description

Based on holotype male (3.1 mm). Head longer than pereonites 1 and 2 together; lateral cephalic lobe acute; eyes absent; anteroventral margin strongly recessed. Antennae 1 and 2 missing. Epistome acute and turned upwards. Mandible lacinia mobilis asymmetric; palp article 2 longer than article 3, with many slender setae; article 3 spatulate with long sub to apical setae and a row of facial setae. Maxilla 1 inner plate with one long seta; outer plate with nine robust setae; palp longer than outer plate with four apical robust setae and two facial slender setae. Maxilliped inner plate rectangular with two apical short robust setae; outer plate ovate, reaching more than one-half of palp article 2; palp 4-articulate, article 4 slightly shorter than article 3 with apical nail. Upper lip, lower lip, and maxilla 2 with basic characters for the genus.

Coxae 1–7 wider than long. Coxae 5–6 excavate distally. Gnathopod 1 basis slender; propodus triangular, setose, and longer than carpus, palm acute and crenulated; dactylus fitting palm. Gnathopod 2 basis with five setae on posterior margin, anterodistal angle with a short process; carpus triangular and short; propodus massive, 2.6 × carpus length, palm shorter than posterior margin with two processes, first one proximal and triangular dentate on anterior part, second one blunt, both separated by a deep U-shaped excavation followed by a concave crenulate portion, palmar corner defined by well-developed acute process, facial margin with one pair of one short seta and one long robust seta, inner face with two robust setae; dactylus stout with a spine about twothirds its length. Pereopod 3 basis rectangular and slender, longer than merus and carpus together; merus with anterior margin produced; propodus longer than carpus; dactylus shorter than propodus. Pereopods 4 and 5 missing. Pereopod 6, basis with posterior margin sinuous; merus longer than carpus with posterior margin produced; carpus 0.7 × propodus length; propodus long; dactylus about twothirds propodus length. Pereopod 7 missing.

Epimera 1–3 rounded. Uropods 1 and 2 reaching apex of uropod 3 equally. Uropod 1 peduncle inner margin with three marginal and one distolateral robust setae, outer margin with five marginal and one distolateral setae; interamal process about one-fifth of peduncle length; rami with one apical setae; inner ramus longer than outer ramus, with two short robust setae about halfway along ramus length; outer ramus with three short robust setae about halfway along ramus length. Uropod 2 inner margin longer than outer ramus, both with two marginal robust setae and one apical seta; interamal process short and blunt. Uropod 3 peduncle 1.2 × outer ramus length, with one marginal and one distolateral robust setae; inner ramus longer than outer ramus, naked; outer ramus with five subapical tiny spines. Telson triangular, longer than wide, with two dorsal slender setae and three pairs of pappose setae, tip acute.

Sexually dimorphic characters

Females differs from males in two ways: first by a more inflated body; and second in the shape of gnathopod 2, which has the basis slender with setae on both anterior and posterior margins, propodus 1.6 × carpus length, and palm acute with two crenulate portions separated by a triangular process followed by a shallow oblique excavation, and palmar corner with two robust setae.

Remarks

Bonnierella laurensi sp. nov. is closely related to B. campensis sp. nov. in having pereopod 6 with a sinuous basis and uropod 3 with elongate rami; however, it differs from B. campensis sp. nov. by the gnathopod 1 with a triangular propodus, the shape of the palmar processes of gnathopod 2, setose uropods 1 and 2, the peduncle of uropod 3 with one robust seta on the anterior margin, the outer ramus 1.2 × peduncle length, and the more setose telson. Also, the female of B. laurensi sp. nov. has gnathopod 1 with the basis setose, the palmar margin with a welldeveloped triangular process, and only two robust setae on the palmar corner.

Bonnierella laurensi sp. nov. also resembles B. lapisi in the shape of gnathopods 1 and 2, and the maxilliped. Nevertheless, it is quite different in the less setose gnathopods, the U-shaped excavation in the palm of the male gnathopod 2, more elongate rami of uropods 1–3, and the setose telson. Females of B. laurensi have a triangular process on the palm of gnathopod 2, whereas B. lapisi has a deep V-shaped excavation.

The shape of the male gnathopod 2 of B. laurensi sp. nov. and B. californica , as well as the basis of pereopod 6, are very similar. On the other hand, B. laurensi sp. nov. shows pronounced sexual dimorphism, less setose gnathopods, a triangular propodus, and a short dactylus of gnathopod 1, as well as the telson with an acute tip ( Table 5).

Geographic distribution

South Atlantic: Campos Basin, Rio de Janeiro, Brazil.

BONNIERELLA LINEARIS J.L. BARNARD, 1964

( FIGS 14–15 )

Bonnierella linearis J.L. Barnard, 1964: 43 , fig. 33. Bonnierella linearis linearis J.L. Barnard, 1966: 63 . Material examined

Holotype: Male (4 mm), station V-15-69, off Peru, 10°13′S, 80°05′W, 6324 m, 9 December 1958, AMNH 12348 .

Paratypes: Eighteen males and 13 females, station V- 15-69, off Peru, 10°13′S, 80°05′W, 6324 m, 9 December 1958, RV Vema col., AMNH 12351 .

Type locality

Off Peru, 10°13′S, 80°05′W .

Description

Based on holotype male (4 mm). Head, lateral cephalic lobe acute; eyes absent; anteroventral margin strongly recessed. Antennae 1 and 2 missing. Epistome acute and turned upwards. Mandible palp article 1 with marginal setae; article 2 shorter than article 3, with marginal and facial setae; article 3 spatulate, with long sub to apical row of setae. Maxilla 1 inner plate with one distal seta. Maxilliped inner plate rectangular, with three apical short robust setae; outer plate ovate, extending to about one-third of palp article 2; palp 4-articulate, article 4 longer than article 3 without apical nail. Upper lip, lower lip, and maxilla 2 with basic characters for the genus.

Coxae 1–7 wider than long. Coxa 5 excavate distally. Gnathopod 1 basis slender; propodus subovoid, slightly longer than carpus, both weakly setose; palm evenly rounded and crenulated; dactylus fitting propodus. Gnathopod 2 basis anterior margin without setules, anterodistal angle produced, posterior margin almost straight; carpus triangular and short; propodus massive, 3.2 × carpus length, palm longer than posterior margin, with two processes separated by a U-shaped excavation, first process proximal and crenulate, and second process acute; palmar corner defined by a well-developed spine; dactylus stout, reaching palmar corner. Pereopods 3 and 4 similar in shape and length; basis rectangular, long, and slender, longer than merus and carpus together, anterior margin with some slender setae; merus with anterior margin slightly produced; propodus longer than carpus; dactylus shorter than propodus. Pereopod 5, basis rectangular, posterior margin straight; merus longer than carpus; carpus 0.56 × propodus length; propodus long; dactylus about one-half propodus length. Pereopod 6 basis rectangular, posterior margin straight; merus 1.5 × carpus length; carpus 0.54 × propodus length; propodus long; dactylus more than one-half propodus length. Pereopod 7 basis rectangular, posterior margin straight; merus 1.5 × carpus length; carpus 0.6 × propodus length; propodus long; dactylus about onethrid propodus length.

Epimera 1–3 rounded. Uropods 1 and 2 reaching equally apex of uropod 3. Uropod 1 peduncle inner margin with three marginal robust setae and one distal robust seta, outer margin with two marginal setae; interamal process about one-sixth peduncle length; rami lacking apical setae; inner ramus shorter than outer ramus, without setae; outer ramus with two robust setae. Uropod 2 peduncle inner margin with one marginal robust setae and two distolateral robust setae; interamal process little developed; rami with one apical setae; inner ramus longer than outer ramus, with two robust setae; outer ramus with one robust setae. Uropod 3 peduncle 2 × outer ramus length, with two distal robust setae; inner ramus longer than outer ramus, with two marginal setae; outer ramus with subapical tiny spines. Telson triangular, with four subapical and four lateral setae, tip acute.

Sexually dimorphic characters

Female with pronouced sexual dimorphism. Differs from male by less robust gnathopod 2, which lacks the palmar corner, and the two palmar processes are subacute, instead of crenulate.

Additional description

Based on paratype female (3.8 mm), AMNH 12351. Antenna 1 article 1 about 0.5 × article 2 length; article 3 longer than article 2; accessory flagellum 2-articulate, first article long and second article rudimentary; primary flagellum longer than peduncle, with eight articles. Antenna 2 article 4 shorter than article 5; flagellum shorter than peduncle, with seven articles.

Remarks

Bonnierella linearis J.L. Barnard, 1964 was described from off Peru. Later on, J.L. Barnard (1966) described B. californica from the Tanner Basin of southern California as a subspecies of B. linearis . Nevertheless, the distinctive character states detailed by J.L. Barnard seem to be sufficient to warrant specific rank for these taxa.

Indeed, B. linearis is very close to B. californica , but these species are quite different from each other in a number of character states. As a whole, B. californica is distinguished from B. linearis by: article 1 of mandibular palp lacking setae and about 0.15 × length of article 2; male gnathopod 2 with a lobate process near the hinge of the dactylus (versus a multicrenulate process); gnathopod 1 of both males and females more setose; basis of pereopods 3 with several setae along both anterior and posterior margins; outer ramus of uropod 1 0.7 × peduncle length (versus 0.3×); outer ramus of uropod 3 0.6 × peduncle length (versus 0.5×); and telson with a rounded tip (versus acute tip).

Also, the female of B. californica can be separated from B. linearis by gnathopod 2 with a well-developed palmar corner. Although J.L. Barnard (1966) considered this character a matter of age difference, the paratype female of B. linearis (3.4 mm) is larger than that of B. californica (2.75 mm). Therefore, we considered these characters as valid in separating these species from each other. For comparison with other species, see Table 5.

Geographic distribution

Known only from the type locality.

Figures

Figure 11. Bonnierella laurensi sp. nov. Holotype: male (3.1 mm), OCEANPROF II, BC-SUL, #84, 1050 m, 20 June 2003, MNRJ 21231.

Figure 12. Bonnierella laurensi sp. nov. Holotype: male (3.1 mm), OCEANPROF II, BC-SUL, #84, 1050 m, 20 June 2003, MNRJ 21231.

Figure 13. Bonnierella laurensi sp. nov. Holotype: male (3.1 mm), OCEANPROF II, BC-SUL, #84, 1050 m, 20 June 2003, MNRJ 21231. Paratype: female (3.2 mm), OCEANPROF II, BC-SUL, #84, 1050 m, 20 June 2003, MNRJ 21422.

Figure 14. Bonnierella linearis J.L. Barnard, 1964. Holotype: male (4 mm), station V-15-69, off Peru, 10°13′S, 80°05′W, 6324 m, 9 December 1958, AMNH 12348. Habitus redrawn from Barnard (1964), with permission from the American Museum of Natural History.

Figure 15. Bonnierella linearis J.L. Barnard, 1964. Holotype: male (4 mm), station V-15-69, off Peru, 10°13′S, 80°05′W, 6324 m, 9 December 1958, AMNH 12348. Paratype: female (3.8 mm), station V-15-69, off Peru, 10°13′S, 80°05′W, 6324 m, 9 December 1958, RV Vema col., AMNH 12351.