Spongiopsyllus atypicus, Canário & Hurbath & Da Rocha & Neves & Johnsson, 2019

Canário, Roberta, Hurbath, Thiego, Da Rocha, Carlos E. F., Neves, Elizabeth G. & Johnsson, Rodrigo, 2019, Description of a new species of Spongiopsyllus Johnsson, 2000, and redescriptions of Parmulodes verrucosus Wilson, 1944 and Entomopsyllus stocki Kim, 2004 with revised diagnosis of Entomopsyllus (Copepoda, Siphonostomatoida, Entomolepididae), Zootaxa 4612 (2), pp. 247-259 : 249-253

publication ID	https://doi.org/ 10.11646/zootaxa.4612.2.7
publication LSID	lsid:zoobank.org:pub:F07FA574-675E-4F90-8466-E64E1C29127E
persistent identifier	https://treatment.plazi.org/id/BB3E87F9-5177-FFDA-FF55-FE0BFEBF5889
treatment provided by	Plazi
scientific name	Spongiopsyllus atypicus
status	sp. nov.

Treatment

Spongiopsyllus atypicus sp. nov.

( Figs 1–3 View FIGURE 1 View FIGURE 2 View FIGURE 3 A–C)

Material examined. Holotype ♀ ( UFBA 3294 ), alotype ( UFBA 3295 ) and 1 paratype ( UFBA 3296 ), Porto da Barra Beach , Todos-os-Santos Bay, Salvador city, Bahia State, Brazil, collected by LABIMAR, 31, August 2016. Associated with sponge Aplysina insularis . Holotype ( UFBA 3294 ) dissected and mounted on slide . Paratype and allotype preserved in ethanol.

Description of female. Mean body length (excluding caudal setae) 1,155 µm (1,150 –1,160 µm) and mean body width 719 µm (717–721 µm) (n =2). Body ( Fig. 1A View FIGURE 1 ) with prossomal shield flattened, well-sclerotized, showing radiation bands along outer margin. Pedigerous somites 2–4 free. Pedigerous somite 4 expanded, covering urosome except the tip of caudal rami.

Urossome 4-segmented ( Fig. 1B View FIGURE 1 ). Genital double-somite fused with fifth pedigerous somite, 150 µm long and maximum width 132 µm, length: width ratio = 1.1:1, vestigial leg 6 located anterolaterally with minute seta, close to genital openings. Setulated groove mid posteriorly on genital somite, reaching posterior margin. Three postgenital somites present; first one longer than wide (62 × 60 µm); second and third somites wider than long (38 × 55, 50 × 60 µm, respectively). Caudal rami elongate, 120 × 19 µm. Length: width ratio 6.3: 1 µm, armed with six setae; seta I absent.

Antennule ( Fig. 1C View FIGURE 1 ) slender, 257 µm long (excluding setae), 14-segmented. Length of segments measured in proximal to distal order: 61, 19, 34, 9, 9, 10, 11, 11, 11, 10, 10, 9, 9, and 18 µm, respectively. Segmental homologies and setation as follows: 1(I)-1; 2(II)-1; 3(III-VIII)-9; 4(IX-XIII)-7; 5(XIV)-1+I; 6(XV)-1; 7(XVI)-1; 8(XVII)- 1; 9(XVIII)-2; 10(XIX)-1; 11(XX)-1; 12(XXI)-1+ae; 13(XXII-XXIII)-0; 14(XXIV-XXVIII)-11; all setae smooth. Aesthetasc 82 µm long.

Antenna ( Fig. 1D View FIGURE 1 ) 218 µm long (including distal claw); coxa and basis unarmed. Exopod 1-segmented, 64 µm long with smooth distal seta and seven lateral setules. Endopod 2-segmented, first segment 54 µm long, unarmed, with setules along outer margin; second segment 27 µm long armed with long proximal lateral seta on outer margin and three subdistal setae on inner, outer and medial margin. The latter seta is the longest one and is located close to distal claw, 46 µm long, slightly curved distally. Two rows of setules on second endopodal segment.

Oral cone 625 µm long, reaching to genital double-somite ( Fig. 1A View FIGURE 1 ). Mandible comprising stylet and slender 2-segmented palp ( Fig. 1E View FIGURE 1 ) measuring 43 and 40 µm long, respectively. Second segment with 2 naked distal setae. Both setae broken. Maxillule bilobed ( Fig. 1F View FIGURE 1 ), both lobes armed with four setae, outer lobe 39 µm long with row of setules on outer margin; inner lobe with 54 µm long. Maxilla ( Fig. 1G View FIGURE 1 ) with syncoxa 162 µm long and claw with distal portion curved at a 90° angle, 137 µm long.

Maxilliped ( Fig. 2A View FIGURE 2 ) 5-segmented, 234 µm long; syncoxa 40 µm long with naked seta on inner margin; basis 93 µm, unarmed. Endopod 3-segmented, segments measuring 23, 18 and 22 µm long, respectively; first segment with two long setae; second segment unarmed; third segment with small seta close to distal claw-like element with curved tip and measuring 38 µm long.

Legs 1-3 ( Fig. 2 View FIGURE 2 B-D) biramous, with 3-segmented rami. Leg 4 ( Fig. 2E View FIGURE 2 ) with 3-segmented exopod and endopod absent. Armature formula as follows:

Leg 1 with very long and naked inner seta on basis, first endopodal segment very enlarged, second and third endopodal segments prolonged distally into sharpened process, therefore distal setae of third segment located subdistally on inner margin ( Fig. 2B View FIGURE 2 ). Exopodal segments of legs 1 to 4 with setules on outer margins ( Figs 2 View FIGURE 2 B-E). Legs 2 and 3 with second endopodal segments with setules on both margins and third endopodal segments with few setules on outer margin ( Figs 2 View FIGURE 2 C–D). Leg 3 with first endopodal segment unarmed, with setules on outer margin and dilatated subdistally; third endopodal segment very short, half the length of previous segment and armed with 2 setae ( Fig. 2D View FIGURE 2 ). Leg 4 bearing minute outer basal seta ( Fig. 2E View FIGURE 2 ).

Free exopodal segment of leg 5 ( Fig. 1B View FIGURE 1 ) elongated, curved, 196 µm long, almost reaching distal margin of first post-genital somite, armed with 2 distal setae and one outer seta medially; all setae plumose.

Description of male. Body ( Fig. 3A View FIGURE 3 ) similar to female, but much smaller. Body length (excluding caudal setae) 718 µm and body width 535 µm. Prosomal shield flattened with radiation bands along outer margin. Pedigerous somites 2–4 free. Pedigerous somite 4 expanded, covering urosome.

Urosome 5-segmented ( Fig. 3B View FIGURE 3 ). Genital somite fused with fifth pedigerous somite, 108 µm long and maximum width 151 µm, and length: width ratio 0.7:1. First, third and fourth postgenital somites wider than long (21 × 53, 13 × 48, 38 × 48 µm, respectively); second somite almost as long as wide (51 × 50 µm); First and second postgenital somites with tooth-like projections on each distal lateral margins. Prosome: urosome length ratio 3.4:1. Caudal rami elongated, 55 µm long, armed with six setae; seta I absent, setae II to VII present.

Antennule ( Fig. 3C View FIGURE 3 ) slender, 219 µm long (not including setae), 14-segmented. Length of segments measured in proximal to distal order: 45, 19, 22, 8, 10, 4, 5, 13, 24, 9, 17, 18, 21 and 15 µm, respectively. Segmental homologies and setation as follows: 1(I)-1; 2(II)-2; 3(III-VI)-8; 4(VII)-1; 5(VIII)-2; 6(IX–XII)-8; 7(XIII)-1; 8(XIV)-1; 9(XV- XVI)-4; 10(XVII)-2; 11(XVIII)-2; 12(XIX-XX)-2; 13(XXI-XXIII)-4+ae; 14(XXIV-XXVIII)-13; all setae smooth. Aesthetasc 85 µm long. Oral cone ( Fig. 3A View FIGURE 3 ) 400 µm long, reaching first post-genital somite. All other appendages as in the female.

Type locality. Porto da Barra Beach (13°00’13.5”S, 38°32’02.6”W), Salvador GoogleMaps city, Bahia State, Brazil .

Etymology. The specific name ‘ atypicus ’ is a combination of the prefix ‘a’, that means no, with the Latin word ‘typicus’, that means ‘relative to a type’ referring to uncommon and unique characteristics of the new species. Among these characteristics we may point the presence of an outer seta on leg 4 basis, the maxillule with 4 setae on each lobe and the extremely long inner seta on the basis of leg 1.

Remarks. Spongiopsyllus atypicus sp. nov. has antennule 14-segmented differing from all others Spongiopsyllus species: S. adventicius and S. redactus have the antennule 17 and 15-segmented respectively ( Johnsson 2000; Canário et al. 2012). Indeed, S. atypicus sp. nov. possesses four setae on both lobes of maxillule as differing from S. adventicius and S redactus that have three setae on each lobe ( Johnsson 2000; Canário et al. 2012). The armature formula of the endopod of the maxilliped in the new species is 2,0,1+claw while in S. adventicius and S. redactus is respectively 0,2,1+claw and 2,1,1+claw. Besides that, the segments and distal claw are shorter and blunter ( Johnsson 2000; Canário et al. 2012). Among the other unique features of the S. atypicus sp. nov. are the outer seta on the basis of leg 4, the the extremely long inner seta on the basis of leg 1. These characteristics are not found in any other species of the genus.