Pseudoprotella australiensis, Guerra-García & Ahyong, 2020

Guerra-García, José M. & Ahyong, Shane T., 2020, A New Genus and Two New Species of Caprellidae (Crustacea: Amphipoda) from Mesophotic and Deep-sea Waters of Australia, Records of the Australian Museum 72 (2), pp. 45-62 : 52-61

Pseudoprotella australiensis sp. nov.

http://zoobank.org/NomenclaturalActs/ 439B99F5-7E80-4219-9104-AE62535658D6

Figs 6–12

Holotype: AM P.101359, mature male (vial + 2 slides) (mouthparts dissected, used for description, figured), southeast of Broken BaY , New South Wales, Australia, 33°36'S 151°30'E to 33°37'S 151°29'E, 71–75 m, FRV Kapala , beam trawl, fixed in formalin, preserved in 80% ethanol, 10 FebruarY 1986 . Paratypes: (same collection data as the holotYpe) : AM P.101360, paratype “a”, mature female (vial + 2 slides) (mouthparts dissected, used for description, figured) ; AM P.101361, paratype “b”, mature female (vial, no slides) (mouthparts not dissected) ; AM P.101362, paratype “c”, mature female (vial + 2 slides) (mouthparts dissected) ; AM P.101363, paratype “d”, mature male (vial, no slides) (mouthparts not dissected) ; AM P.101364, paratype “e”, juvenile male (vial, no slides) (mouthparts not dissected, figured) ; AM P.101365, paratype “f”, premature female (vial, no slides) (mouthparts not dissected, figured) ; AM P.101366, 25 mature males, 11 mature females, 3 premature females (vial containing all these specimens, no slides).

Other material examined. New South Wales, Australia: AM P.101367, 1 mature male, east of Long Reef Point , 33°46'S 151°43'E, 176 m, FRV Kapala , dredge, 5 December 1977 ; AM P.101368, 1 mature female, south-east of Broken BaY , 33°41'S 152°01'E, 1125 m, FRV Kapala , 11 December 1978 ; AM P.101369, 1 mature male, east of Long Reef , 33°46'S 151°48'E, 403 m, FRV Kapala , 3 December 1979 ; AM P.101370, 2 mature males, 2 mature females, 2 juveniles, east of Port Jackson , 33°52'S 151°23'E, 80 m, FRV Kapala , epibenthic sled, coll . R. T. Springthorpe , 11 December 1980 ; AM P.101371, 1 mature male, 1 mature female, east of Port Jackson , 33°50'S 151°32'E to 33°50'S 151°34'E, 132–135 m, FRV Kapala , trawl, 18 December 1985 ; AM P.101372, 3 mature females, east of Long Reef , 33°44'S 151°53'E to 33°43'S 151°54'E, 494–518 m, FRV Kapala , trawl, 18 December 1985 ; AM P.101373, 2 mature females, east of Long Reef , 33°43'S 151°46'E to 33°44'S 151°46'E, 174 m, FRV Kapala , epibenthic sled, coll. J. K. LowrY , R. T. Springthorpe , 20 December 1985 ; AM P.101374, 3 mature males, 1 premature female, 1 mature female, east of BarrenjoeY Headland , 33°36'S 151°26'E to 33°36'S 151°27'E, 56 m, FRV Kapala , trawl, 10 FebruarY 1986 ; AM P.101378, 1 mature male, south-east of Disaster BaY , 37°23'54"S 150°17'54"E, 161–184 m , RV Southern Surveyor , benthic sled, coll. P. B. Berents, 1 September 1994 ; AM P.101379, 3 mature males, 1 premature female, 1 juvenile, east of Disaster BaY , 37°19'24"S 150°11'18"E, 107–110 m , RV Southern Surveyor , benthic sled, coll. P. B. Berents, 1 September 1994 ; AM P.101380, 1 mature male, east of Disaster BaY , 37°18'36"S 150°03'54"E, 81–82 m , RV Southern Surveyor , benthic sled, sediment, coll. P. B. Berents, 2 September 1994 ; AM P.101381, 2 mature females east of Disaster BaY , 37°18'42"S 150°00'48"E, 42–44 m , RV Southern Surveyor , benthic sled, coll. P. B. Berents, 2 September 1994 ; AM P.101382, 1 mature male east of Merimbula , 36°55'48"S 149°58'06"E, 43–44 m , RV Southern Surveyor , benthic sled, coll. P. B. Berents, 3 September 1994 ; AM P.101383, 1 mature female, east of Bermagui , 36°23'18"S 150°10'36"E, 76–79 m , RV Southern Surveyor , benthic sled, sediment, coll. P. B. Berents, 5 September 1994 ; AM P.101384, 2 mature females, east of Bermagui , 36°22'00"S 150°06'42"E, 26 m , RV Southern Surveyor , benthic sled, pebbles and coarse gravel, coll. P. B. Berents, 6 September 1994 ; AM P.101385, 1 mature female, east of Bermagui , 36°25'12"S 150°18'30"E, 220 m , RV Southern Surveyor , benthic sled, coll. P. B. Berents, 5 September 1994 .

Victoria, Australia: AM P.101376, 1 mature male Bass Strait , east of Seal Islands, 38°59'06"S 148°31'36"E, 125 m , RV Southern Surveyor , benthic sled, 27 August 1994, coll. P. B. Berents ; AM P.101377, 1 mature female, south of Gabo Island , 37°51'06"S 149°50'42"E, 130–131 m , RV Southern Surveyor , benthic sled, sponge, 31 August 1994, coll. P. B. Berents.

Tasmania, Australia: AM P.101375, 1 mature male, off St. Helens Point , 41°20'36"S 148°30'00"E, 110 m , RV Sprightly, fine claYeY sand, preserved 80% ethanol, 25 March 1973, coll. P. H. Colman.

Etymology. The specific epithet “australiensis” alludes to the continent from which the species has been found, Australia.

Diagnosis. EYes with distinctive ommatidia. Head with an anteriorlY curved dorsal acute projection. Pereonites 2–6 with tinY tubercles scattered on the surface. Maxilliped palp article 3 without distal projection. Mandibular palp 3-articulate, with the setal formula 2-x-1, with x = 11; molar triturative, molar flake present. Maxilla 1 outer lobe with 6 distal spines. Gnathopod 2 basis shorter than pereonite 2. Pereopods 3 and 4 2-articulate; proximal article larger than distal article; distal article conical. Pereopods 5–7 6-articulate. Abdomen without appendages (no distinctive pleopods).

Description. Holotype male AM P. 101359 (11.3 mm)

Lateral view ( Fig. 6 ). Head with an anteriorlY curved dorsal acute projection. EYes with distinctive ommatidia. Pereonite 1 fused with head, suture present. Pereonites 2–6 with tinY tubercles scattered on surface. Pereonites 2–5 dorsal surface also with pair of rounded medial tubercles, slightlY larger than those scattered on bodY surface. Pereonites 2 and 3 also with small proximal projection dorsallY and row of small rounded projections laterallY from head to coxa, and acute projection mediallY near coxa (see detail in Fig. 6 ). Pereonites 3 and 4 also ornamented with anterolateral row of small projections. Pereonite 5 the longest. Pereonite 7 smooth, the shortest.

Gills ( Fig. 6 ). Present at middle of pereonites 3 and 4, elongate, length about 3 × width.

Mouthparts ( Figs 7 , 8 ). (Maxilla 1, maxilla 2, upper lip and mandibles figured and described from holotYpe male; maxilliped and lower lip figured and described from paratYpe “a” female). Mandibles with strong and triturative molar; palp 3-articulate; setal formula 2-x-1 with x=11, row of tubercles present near the base of setae (see details in Fig. 7 ); left mandible with incisor and lacinia mobilis 5-dentate, followed bY 3 accessorY blades; right mandible incisor 5-dentate, lacinia mobilis blade-like, followed bY 2 more blades; molar flake present. Upper lip with verY fine setulae. Lower lip without setae; inner lobes apparentlY with medial cleft but not clearlY marked. Maxilla 1 outer lobe carrYing 6 spines, palp 2-articulate, distal article with medial seta and 4 setae distallY, together with 3 small distal teeth. Maxilla 2 inner lobe triangular, small; outer lobe rectangular, twice as large as inner lobe. Maxilliped inner plate small, length about 1/3 outer plate length, with 3 plumose setae and small tooth; outer plate with 3 setae; palp 4-articulate, article 4 curved distallY and with row of tinY setulae.

Antennae ( Figs 6 , 9 ). Antenna 1 about 1/2 bodY length; flagellum 15-articulate, basal article 1, 3× length of article 2. Antenna 2 about 1/2 length of antenna 1; proximal peduncular article with acute gland cone distallY; article 2 with 2 spines distallY instead of setae; swimming setae absent; flagellum 2-articulate.

Gnathopods ( Figs 6 , 9 , 10 ). Gnathopod 1 longer than ischium, merus and carpus combined; occlusal margin of propodus minutelY serrated; 2 proximal grasping spines, dactYlus bifid distallY and provided with row of setulae. Gnathopod 2 inserted on anterior half of pereonite 2; coxa well developed (see detail in Fig. 6 ); basis about 2/3 length of pereonite 2, provided with small proximal internal projection near coxa and distal projection laterallY; ischium rectangular; merus rounded; carpus short and triangular; propodus with distal projection dorsallY together with plumose seta; palm with proximal projection provided with large grasping spine, serrated area, medial projection, and 2 more projections distallY (see Fig. 9 ); dactYlus smooth, slightlY curved.

Pereopods ( Figs 6 , 10 , 11 ). Pereopod 3 and 4 2-articulate; basal article with 2 setae, distal article conical with 2 lateral plumose setae and distal seta. Pereopods 5–7 with well-developed coxae (see details of Fig. 6 ). Pereopod 5 inserted on distal end of pereonite 5, elongate, provided with abundant plumose setae and lacking defined grasping spines. Pereopods 6 and 7 more robust than pereopod 5, with plumose setae, palm of propodus with pair of stronger plumose setae appearing as grasping spines (on pereopod 7 these 2 setae are inserted on a proximal projection).

Penes ( Fig. 11 ) large, situated laterallY, cleft distallY, elongate, length about 3× width.

Abdomen ( Fig. 11 ) lacking appendages, a pair of lobes with cluster of setae, and single dorsal lobe with 2 plumose setae.

Paratype female “a” AM P. 101359 (9.7 mm) ( Figs 6 , 8 , 10 , 11 ). VerY similar to male apart from the presence of setose oostegites on pereonites 3 and 4, lack of penes, and lateral lobes of abdomen provided with single seta instead of a cluster of setae .

Intraspecific variation and ontogenetic development. Most of the morphological characters of the species are rather constant in all the specimens examined. BodY dorsal tuberculation is similar in all the specimens, with the formula: Head+P1 (1), P2 (1+2), P3 (1+2), P4 (2), P5 (2), P6 (0), P7 (0) (number of tubercles in parentheses, except for Head+P1 where the number indicates acute projection). In some females, pereonite 2 lacks medial dorsal projections, and in some males, pereonite 4 also has a proximal projection as in pereonite 3. In connection with the mouthparts, the maxilla 1 outer lobe is alwaYs provided with six spines and the distal article of the palp carries four distal and one medial spine. Each lobe of maxilla 2 is provided with six to eight setae. The maxilliped inner plate is alwaYs provided with three setae, the inner two alwaYs being plumose, and the third, external, plumose in some specimens and not plumose in others. This inner plate can have 1 or 2 small teeth, and the outer plate has 2 or 3 distal setae. The setal formula of mandibular palp is 2-x-1 (with x = 11 in all specimens examined), although some specimens have an additional long seta proximallY which could be considered as 3-x-1.

Regarding ontogenetic development ( Fig. 12 ), the flagellum of antenna 2 is alwaYs 2-articulate. The number of articles of the flagellum of antennae 1 increases with development. Pereonite 2 of immature males and females lacks the small proximal dorsal round projection, and dorsal tubercles of peronites 2–5 are less developed than in mature specimens. The number of tinY tubercles scattered on the bodY surface is also lower in immature individuals and the lateral ornamentation on the proximal part of pereonites 2, 3 and 4 is less developed. The gnathopod 2, rather similar in males and females, does not change significantlY during development; the distal dorsal projection of the propodus is alreadY present in immature specimens. In adults of both sexes, gills of pereonites 3 and 4 are of the same length. In some larger males gills 3 become larger than gills 4.

Remarks. Four species of Pseudoprotella have been described so far: Pseudoprotella phasma (Montagu, 1804) , Pseudoprotella inermis Chevreux, 1927 (redescribed bY Guerra-GarcÍa & Takeuchi, 2000), Pseudoprotella soela Guerra-GarcÍa, 2004b and Pseudoprotella bogisa ( MaYer, 1903) , which was recentlY transferred from the genus Noculacia to Pseudoprotella mainlY on the basis of the presence of a well developed molar, the structure of pereopods 3 and 4 and the setal formula of the mandibular palp being 2-x-1 (see Guerra-GarcÍa, 2002). A comparison of Pseudoprotella spp. is provided bY Guerra-GarcÍa (2002). Pseudoprotella inermis is restricted to the Strait of Gibraltar area and North Atlantic coast of Morocco ( Guerra-GarcÍa & Takeuchi, 2000; Guerra-GarcÍa et al., 2014) and it is characterized bY the total absence of dorsal bodY projections. Pseudoprotella bogisa has been collected so far onlY from Thai waters ( McCain & Steinberg, 1970; Guerra-GarcÍa, 2002), and Pseudoprotella soela from Western Australia ( Guerra-GarcÍa, 2004b). Pseudoprotella phasma sensu lato is distributed in the Mediterranean Sea and Atlantic Ocean, and includes several forms (f. typica, f. minor, f. quadrispinis and f. bispinis) described bY MaYer (1890, 1903) and two additional ones collected from deep-sea areas of the northwestern Iberian Peninsula and figured bY Guerra-GarcÍa et al. (2018). Hence, P. phasma , as presentlY understood, probablY includes at least six different species, which are still awaiting proper description and/or new appraisal of species ranking. A full revision of Pseudoprotella with detailed morphological and molecular data is, therefore, mandatorY to clarifY the taxonomical status of P. phasma sensu lato from shallow waters of the Mediterranean and Atlantic ( Guerra-GarcÍa et al., 2018).

The new species, P. australiensis , can be differentiated from all the remaining species of Pseudoprotella mainlY on the basis of the unique bodY ornamentation (acute projection on the head, pereonites with abundant tinY tubercles scattered on the surface, and rows of lateral tubercles on the proximal end of pereonites 2–4). The new species is closer to P. bogisa than to remaining species, mainlY on the basis of the following characters: (i) distal article of pereopods 3 and 4 is conical and smaller than proximal one in P. australiensis and P. bogisa while it is not conical in P. soela and it is ovalrectangular and larger than the proximal one in P. phasma and P. inermis ; (ii) maxilla 1 outer lobe is provided with 6 strong spines in P. bogisa and P. australiensis , while the remaining species have onlY 5 strong spines. A female of Pseudoprotella found in deep-sea water of Azores and figured bY Guerra- GarcÍa (2004a: 25, fig. 17) shows a combination of maxilla 1 with six strong spines and pereopods 3 and 4 with distal articles larger than proximal ones. This, together with the presence of two undescribed forms found in deep-sea Galician waters of the northwestern Iberian Peninsula indicates that a detailed studY of P. phasma sensu lato from deep-sea waters of the Mediterranean and Atlantic Ocean is necessarY to clarifY the taxonomical status of the species of Pseudoprotella .

The new species, P. australiensis , seems to be abundant in mesophotic and deep-sea waters of southeastern Australia including New South Wales, Victoria and Tasmania from 56 to 1125 m depth. Although there are no ecological data accompanYing most of the samples, the species has been collected mainlY from sediments (fine claYeY sand, pebbles and coarse gravel) and sponges .

ACKNOWLEDGMENTS. The present studY was funded bY a grant “Salvador Madariaga” of the “Ministerio de Ciencia, Innovación Y Universidades”. Special thanks to our colleagues of the Australian Museum, Marine Invertebrates Department, for hospitalitY and help during the studY.

Figures

Figure 6. Pseudoprotella australiensis sp. nov. Lateral view of holotYpe male AM P.101359 and paratYpe “a” female AM P.101360. Details of eYe, coxae of gnathopod 2 and pereopods and bodY tubercles ornamentation of the male are also included. Scale bars: 1 mm.

Figure 7. Pseudoprotella australiensis sp. nov. Mandibles of holotYpe male AM P.101359. Scale bars: 0.05 mm.

Figure 8. Pseudoprotella australiensis sp. nov. Maxilla 1, maxilla 2, upper lip of holotYpe male AM P.101359; maxilliped and lower lip of paratYpe “a” female AM P.101360. Scale bars: 0.1 mm.

Figure 9. Pseudoprotella australiensis sp. nov. Antenna 1, antenna 2 and gnathopod 1 of holotYpe male AM P.101359. Scale bars: 1 mm (A1, A2), 0.1 mm (Gn1).

Figure 10. Pseudoprotella australiensis sp. nov. Gnathopod 2 and pereopods 3 and 4 of holotYpe male AM P.101359; gnathopod 2 of paratYpe “a” female AM P.101360. Scale bars: 0.5 mm (Gn2), 0.1 mm (P3, P4).

Figure 11. Pseudoprotella australiensis sp. nov. Pereopods 5, 6 and 7 and abdomen of holotYpe maleAM P.101359; abdomen of paratYpe “a” female AM P.101360. Scale bars: 0.05 mm.

Figure 12. Pseudoprotella australiensis sp. nov. Lateral view of immature specimens: paratYpe “e” juvenile male AM P.101364 and paratYpe “f” premature female AM P.101365. Scale bars: 1 mm.