Apseudomorpha brasiliensis, Segadilha & Serejo, 2020

Segadilha, Juliana Lopes & Serejo, Cristiana Silveira, 2020, First records of Pseudozeuxidae and Metapseudinae (Metapseudidae) (Crustacea, Tanaidacea) in Southwestern Atlantic, with descriptions of two new species, Zoosystematics and Evolution 96 (2), pp. 723-745 : 723

publication ID	https://dx.doi.org/10.3897/zse.96.56097
publication LSID	lsid:zoobank.org:pub:3B79D590-23AB-42EB-9ADD-2DEE0A17C4C7
persistent identifier	https://treatment.plazi.org/id/9EE09B11-2A85-4550-A7AC-BE36F698BB68
taxon LSID	lsid:zoobank.org:act:9EE09B11-2A85-4550-A7AC-BE36F698BB68
treatment provided by	Zoosystematics and Evolution by Pensoft
scientific name	Apseudomorpha brasiliensis
status	sp. nov.

Treatment

Apseudomorpha brasiliensis sp. nov. Figures 1 View Figure 1 , 2 View Figure 2 , 3 View Figure 3 , 4 View Figure 4 , 5 View Figure 5 , 6 View Figure 6 , 7 View Figure 7

Material examined.

Holotype: Brazil • 1 ♀ ovigerous, TL 2.4 mm ( MNRJ 29863), Stn CR.AS. - C4B, 7 Sep. 2017, Santana Archipelago, Macaé, Rio de Janeiro, Brazil.

Allotype: Brazil • 1 ♂, TL 1.8 mm ( MNRJ 29864), Stn CR.AS. - C4B, 7 Sep. 2017, Santana Archipelago, Macaé, Rio de Janeiro, Brazil.

Paratypes: Brazil • 1 ♀ ovigerous and 1 ♂, dissected, TL 2.0 mm ( MNRJ 29857) and 1.9 mm ( MNRJ 29858) respectively, Stn CR.AS. - C5B, 7 Sep. 2017, Santana Archipelago, Macaé, Rio de Janeiro; Brazil • 5 ♀ non-ovigerous ( MNRJ 29859), same station; Brazil • 1 ♀ ovigerous ( MNRJ 29860), Stn CR.AS. - C1B, 25 Jun. 2017, Santana Archipelago, Macaé, Rio de Janeiro; Brazil • 1 ♀ non-ovigerous ( MNRJ 29856), Stn CR.AS. - C2B, 7 Sep. 2017, Santana Archipelago, Macaé, Rio de Janeiro; Brazil • 3 ♀ ovigerous, 3 ♀ non-ovigerous and 2 ♂ ( MNRJ 29865), Stn CR.AS. - C4B, 7 Sep. 2017, Santana Archipelago, Macaé, Rio de Janeiro; Brazil • 3 ♀ ovigerous ( MNRJ 29862), Stn CR.AS. - C2C, 7 Sep. 2017, Santana Archipelago, Macaé, Rio de Janeiro; Brazil • 1 ♀ non-ovigerous ( MNRJ 29861), Stn CR.AS. - C5C, 7 Sep. 2017, Santana Archipelago, Macaé, Rio de Janeiro; Brazil • 6 ♀ non-ovigerous and 2 ♂ ( MNRJ 29854), Stn CR.AS. - F3B, 25 Jun. 2017, Cavaleiros, Macaé, Rio de Janeiro; Brazil • 2 ♀ non-ovigerous ( MNRJ 29855), Stn CR.AS. - F3C, 25 Jun. 2017, Santana Archipelago, Macaé, Rio de Janeiro.

Diagnosis.

Female. Rostrum with rounded tubercles at base and bifurcate tip. Pleonites 2 and 5 with pleura having long distal seta. Antennule article-1 inner margin with one blunt apophysis, outer flagellum with three segments. Mandible palp article-2 and article-3 with six and nine finely penicillate setae on inner margin respectively. Maxilliped palp article-1 outer margin with seta. Pereopod-1 basis with dorso-proximal margin lacking blunt, spiniform process; carpus and propodus with two and four ventral spines, respectively. Pereopods 1-2 basis with several setae along ventral margin. Pleopods biramous, exopod and endopod each with one long penicillate seta. Uropod exopod shorter than endopod segments 1-2 combined, endopod with four segments.

Male. Cheliped propodus just wider than long, ventral margin with only three simple setae (without proximal apophysis).

Description.

Based on ovigerous ♀ holotype ( MNRJ 29863) and paratype ( MNRJ 29857).

Body (Figs 1A View Figure 1 , 2A View Figure 2 ). Length 2.4 mm, about 4.8 times L:W.

Cephalothorax (Fig. 2A View Figure 2 ) about 24% of TBL, shorter than pereonites 1-3 lengths combined, about 1.2 times L:W; rostrum convex with broad base, with rounded tubercles at base and median short bifurcate tip (Fig. 2B View Figure 2 ); eyelobes well defined, visual elements present. Carapace with simple seta near each ocular lobe (Fig. 2B View Figure 2 ).

Pereon (Fig. 2A View Figure 2 ) about 60% of TBL, all pereonites wider than long, all with two simple setae on sub-distal dorsal margin and one seta on each anterolateral margins; pereonite-1 wider than others, rectangular with few minute setae on posterolateral margins; pereonites 2-5 longer than pereonite-1; pereonite-6 shortest; pereonites 4-6 with weak anterolateral processes bearing setae.

Pleon (Figs 1A View Figure 1 , 2A, C View Figure 2 ) about 16% of TBL, shorter than pereonites 1-2 lengths combined, about 1.2 times L:W; all pleonites sub-equal, wider than long, bearing pleopods; pleonite-1 laterally rounded (Fig. 2C View Figure 2 ); pleonites 2-5 prominent epimera with round tip (Fig. 2C View Figure 2 ); pleonites 2 and 5 with long simple seta (Fig. 2C View Figure 2 ); pleonites 3-4 with small simple seta (Fig. 2C View Figure 2 ).

Pleotelson (Figs 1A View Figure 1 , 2A, C View Figure 2 ) as long as pereonite-6 (Fig. 2A View Figure 2 ); dorso-anteriorly with two tubercles, each with two simple setae (Fig. 2A, C View Figure 2 ); antero-laterally with tubercle with round tip and bearing simple distal seta (Fig. 2C View Figure 2 ); prominent triangular apex with two sub-distal setae (Fig. 2A, C View Figure 2 ).

Antennule (Fig. 3A View Figure 3 ) shorter than cephalothorax. Peduncle with four articles. Article-1 2.2 times L:W; inner margin with two simple sub-distal setae and one blunt apophysis; outer margin with one distal pointed angle, with one simple and three penicillate setae proximally, with one long and one short simple and two penicillate setae medially, and with three simple setae distally. Article-2 as long as wide; with seven simple and one penicillate setae distally. Article-3 just longer than wide; with two simple distal setae. Article-4 as long as wide; with two middle penicillate and one simple and one penicillate distal setae. Outer flagellum with three segments. Segment-1 slightly longer than wide, with middle and two distal simple setae and one aesthetasc. Segment-2 about 1.3 times L:W; distally with three simple setae and one aesthetasc. Segment-3 2.5 times L:W, distally with five simple setae, one penicillate, and one aesthetasc. Inner flagellum with one segment, 2.8 times L:W, distally with three simple and two penicillate setae.

Antenna (Fig. 3B View Figure 3 ) with eight articles. Article-1 inner margin with rounded distal process. Article-2 inner margin with penicillate seta and distal triangular apophysis; outer margin scaly with two penicillate setae; squama present, longer than article-3, with two distal simple setae. Article-3 wider than long; inner sub-distal margin with simple seta and apophysis. Article-4 inner distal margin with two penicillate setae. Article-5 about 1.3 times L:W, longer than article-4, with two simple and six penicillate setae. Article-6 half-length of article-5, with two simple distal setae. Article-7 longer than article-6, inner distal margin with two simple setae; outer distal margin with simple seta. Article-8 shortest, with three simple and two penicillate distal setae.

Mouthparts: Labrum not recovered. Mandibles (Fig. 3C-D View Figure 3 ). Right mandible incisor with four denticles (Fig. 3C View Figure 3 ); lacinia mobilis with several denticles on dorsal margin (Fig. 3C View Figure 3 ). Left mandible incisor with two denticles (Fig. 3D View Figure 3 ); lacinia mobilis broad with three denticles (Fig. 3D View Figure 3 ); setiferous lobe with four multi-furcate setae (Fig. 3D View Figure 3 ). Molar process of both mandibles damaged during dissection. Palp (Fig. 3D View Figure 3 ) article-1 shortest, inner margin with distal simple seta; article-2 longest, 1.8 times L:W, mid-inner margin with six setulate setae; article-3 with nine setulate inner setae.

Maxillule (Fig. 3E View Figure 3 ). Inner endite not recovered. Outer endite with ten (one setulose) distal and two sub-distal spines, margins finely setose; palp biarticulate with three distal setae.

Maxilla (Fig. 4A View Figure 4 ). Margins finely setose; outer lobe of moveable endite with six setae; inner lobe of moveable endite with six setae; outer lobe of fixed endite with eleven and three plumose setae (Fig. 4A View Figure 4 ); inner lobe of fixed endite with eleven setae. Labium and epignath not recovered.

Maxilliped (Fig. 4B-C View Figure 4 ). Coxa short and wide. Basis finely setose with microtrichia, wider than long, with two denticles on outer distal margin. Palp article-1 shortest, distal inner margin with long (passing article-3) simple seta, and distal outer margin expanded distally with simple seta; article-2 longest, inner margin finely setulose proximally, with 14 simple setae, outer distal margin with strong spine; article-3 inner margin with eight simple setae; article-4 with six simple inner setae and two subdistal outer setae. Endite (Fig. 4B-C View Figure 4 ) with inner margin with seven basally-swollen setulate setae, four simple setae and four apically long simple setae; outer margin setulose with small denticles on mid margin.

Cheliped (Fig. 5A View Figure 5 ). Basis, 1.5 times L:W; ventral margin with distal simple seta. Merus triangular; ventral margin with three simple setae sub-distally. Carpus 2.7 times L:W, just longer than basis, widest distally; ventral margin with one middle and two sub-distal simple setae; dorsal margin with middle and sub-distal simple setae. Propodus 1.9 times L:W; with two simple setae near articulation of dactylus (one long and one small); fixed finger with three ventral simple setae, with five sub-marginal simple setae on outer incisive margin; inner face with sub-distal and mid-ventral simple setae. Dactylus and unguis slightly longer than fixed finger; inner face with simple seta on ventral margin.

Pereopod-1 (Fig. 6A View Figure 6 ). Coxa with two penicillate and four minute setae. Basis 3.6 times L:W; ventral margin with three penicillate and three simple setae, and one spine, one penicillate and one long seta distally; dorsal margin with seven penicillate setae. Ischium with penicillate and simple ventral seta. Merus 1.7 times L:W, widest distally; ventral margin with two simple setae and one sub-distal serrulate spine; outer margin with two middle setulate setae; distodorsal margin with simple seta and serrulate spine. Carpus as long as wide, widest distally, ventral margin with two simple setae and two serrulate spines; outer margin with middle setulate setae; distodorsal margin with penicillate, two simple setae and serrulate spine. Propodus 2.5 times L:W, ventral margin with four serrulate spines and simple seta; outer margin with middle setulate setae; dorsal margin with two penicillate, simple seta and two (one sub-distal and one distal) serrulate spines, and one sub-distal simple seta; inner face with long penicillate and two pectinate setae distally. Dactylus together with unguis shorter than propodus, dactylus longer than unguis; dactylus with two minute ventral setae and small sub-distal denticle. Unguis curved.

Pereopod-2 (Fig. 6B View Figure 6 ) shorter and more gracile than pereopod-1. Coxa with two simple setae. Basis 3.8 times L:W; ventral margin with four simple setae and one long seta distally; dorsal margin with four simple setae. Ischium wider than long, with simple ventral seta. Merus 1.7 times L:W, widest distally; ventral margin with two simple setae and two sub-distal serrulate spines; outer margin with middle simple seta; distodorsal margin with simple seta. Carpus about as long as wide; ventral margin with four serrulate spines; distodorsal margin with four simple setae and two serrulate spines. Propodus 2.6 times L:W; ventral margin with four serrulate spines and two simple setae; dorsal margin with penicillate and two (one sub-distal and one distal) serrulate spines, and one sub-distal simple seta (longer than dactylus); inner face with two pectinate setae distally. Dactylus together with unguis shorter than propodus, dactylus longer than unguis; dactylus with two (one in the middle and one sub-distal) ventral setae and small sub-distal denticle. Unguis curved.

Pereopod-3 (Fig. 6C View Figure 6 ) similar to pereopod-2 but shorter. Coxa seta broken (as in pereopod-4). Basis ventral margin with two penicillate and one simple setae, and one stout seta distally; dorsal margin with penicillate and two simple setae. Ischium with two ventral setae. Merus shorter. Carpus with only two distodorsal setae.

Pereopod-4 (Fig. 6D View Figure 6 ). Coxa with simple seta. Basis three times L:W; ventral margin with two simple and one distal setae; dorsal margin with two penicillate and three simple setae. Ischium wider than long, with two ventral setae. Merus 1.5 times L:W; widest distally; ventral margin with sub-distal simple seta and spine; outer margin with middle setulate seta; distodorsal margin with simple seta. Carpus 1.6 times L:W; ventral margin with two simple setae and four spines; distodorsal margin with five simple setae. Propodus 2.3 times L:W; ventral margin with two spines; outer margin with middle setulate seta; dorsal margin with penicillate seta, and sub-distal spine and simple seta; inner face with row of five sub-distal pectinate plus one long simple setae distally. Dactylus together with unguis shorter than propodus, dactylus longer than unguis; dactylus with two (one in the middle and one sub-distal) ventral setae and small sub-distal denticle. Unguis curved.

Pereopod-5 (Fig. 6E View Figure 6 ) similar to pereopod-4.

Pereopod-6 (Fig. 6F View Figure 6 ) similar to pereopod-5 but slightly smaller. Basis dorsal margin with two penicillate and two simple setae. Ischium with ventral setae. Merus ventral margin with sub-distal simple seta; outer margin with middle setulate seta; distodorsal margin with simple seta. Propodus ventral margin with two spines and simple seta; outer margin with middle setulate seta; dorsal margin with penicillate seta, and sub-distal spine and two simple setae; distally with row of five pectinate and two simple setae.

Pleopods (Fig. 7A View Figure 7 ). Five similar, biramous pairs. Basal article 5.8 times L:W, 2.4 times longer than both rami, naked. Exopod slightly longer than endopod, both uniarticulate and with long plumose seta distally.

Uropod (Fig. 7B View Figure 7 ) biramous. Basal article 1.8 times L:W; inner margin with long distal simple seta; outer margin with one mid and two distal simple setae (one long and one small). Exopod of two segments, shorter than endopod segments 1-2 combined. Segment-1 with two simple distal setae. Segment-2 with two simple distal setae. Endopod shorter than pleon and pleotelson combined, with four segments. Segment-1 with two penicillate and one simple distal setae. Segments 2-4 about same length. Segment-2 with two penicillate and three simple setae on distal margin. Segment-3 with two penicillate and two simple distal setae. Terminal segment with one penicillate and four simple setae distally.

Adult male. Length 1.8 mm. Similar to females except in the size of the chelipeds (allotype and paratype: MNRJ 29864, MNRJ 29858, respectively).

Cheliped (Fig. 5B View Figure 5 ) robust. Basis longer than wide, with one distoventral and two proximal simple setae. Merus with middle and two distoventral simple setae. Carpus broad and short; distoventral margin with a prolongation and three proximal setae. Propodus just wider than long; ventral margin with three simple setae; fixed finger short, with ten sub-marginal simple setae on outer incisive margin; dorsal margin with two denticles and grasping edge, claw short. Dactylus curved, ventral margin with mid-blunt apophysis and grasping edge with row of five thin spines.

Etymology.

The name is dedicated to Brazil, the country where the species were collected.

Type locality.

Eulittoral zone of rocky shores at Santana Archipelago, Macaé, Rio de Janeiro, Brazil.

Distribution.

This species was found exclusively at eulittoral zone on rocky shores (macroalgae bank) of Santana Archipelago, Macaé, Rio de Janeiro, Brazil, Southwestern Atlantic (Fig. 13 View Figure 13 ).

Ecology.

In total, 33 specimens of Apseudomorpha brasiliensis sp. nov. were found in eight of 60 quadrats (13.3%) collected at Santana Archipelago. This species was most abundant in the intermediate stratum (82%), however it was also found in the lower stratum (18%), being absent in the upper stratum. The substrate of the quadrats where the species was found was covered predominantly by articulated calcareous algae ( Rhodophyta), covering a surface between 50-95% (average of 81% of the area). The intermediate stratum presented mainly Rhodophyta macroalgae, although brown algae Ochrophyta also occurred. The predominant Rhodophyta genera were Corallina , Jania and Arthrocardia , with other taxa such as Gracilaria , Hypnea , Pterocladiella and Plocamium . The lower stratum showed a greater coverage of brown algae, mainly of the genera Sargassum , Padina and Colpomenia .

Remarks.

The new species from Brazil is more similar to those Apseudomorpha species characterized by having long setae only on the second and fifth pleonites epimera, namely A. drummi , A. fontainei , A. glebosa , and A. martinicana ( Morales-Núñez et al. 2019). Apseudomorpha brasiliensis sp. nov. differs from A. fontainei by having (1) mandibular palp article-1 with one inner simple distal seta (two in A. fontainei ); (2) pereopods 4-5 carpus distodorsal long seta (longer than half of propodus); (3) biramous pleopods (uniramous in A. fontainei ); and (4) uropod endopod with four segments (seven in A. fontainei ).

Apseudomorpha brasiliensis is different from A. glebosa by (1) pereopod-1 carpus and propodus ventral margin with two and four spines, respectively (three and five in A. glebosa ); (2) pereopod-6 with two ventral spines (four in A. glebosa ); and (3) each pleopod rami with long penicillate seta (only one rami with two setae in A. glebosa ). The new species is distinguished from A. martinicana (1) antennule article-1 inner margin with one blunt apophysis (3-4 apophyses in A. martinicana ); (2) antennule main flagellum with three segments (four in A. martinicana ); (3) mandible palp with article-2 with six inner penicillate setae (three in A. martinicana ); and (4) pereopods 2-3 propodus with four ventral spines (three in A. martinica ).

The new species from Brazil closely resembles A. drummi by having antennule main flagellum with three segments, pereopod-1 carpus and propodus with two and four ventral spines respectively and pleopods with each rami having one long penicillate seta. The former, however, can be distinguished from A. drummi by: (1) antennule article-1 inner margin with one blunt apophysis (three apophyses in A. drummi ); (2) mandible palp article-2 and article-3 with six and nine finely penicillate setae on inner margin respectively (five and eight in A. drummi ); (3) pereopods 1-2 basis with several setae along ventral margin, except distally (maximum one in A. drummi ); (4) uropod exopod shorter than endopod segments 1-2 combined (longer in A. drummi ); and (5) uropod endopod with four segments (five in A. drummi ). These comparisons and others are developed in a key to the species of Apseudomorpha , shown below.

Apseudomorpha brasiliensis is the first record of the subfamily Metapseudinae from the Southwestern Atlantic. Including the present data, the family Metapseudidae is now represented by four genera in three subfamilies in Brazil: Chondropodinae ( Calozodion Gardiner, 1973 and Vestigiramus Guţu, 2009), Metapseudinae ( Apseudomorpha ) and Synapseudinae ( Synapseudes Miller, 1940).