Spongiopsyllus athosi, Farias & Santana & Neves & Johnsson, 2024

Farias, Amilcar, Santana, Alisson, Neves, Elizabeth G. & Johnsson, Rodrigo, 2024, Three new species of Spongiopsyllus Johnsson, 2000 (Copepoda: Siphonostomatoida: Entomolepididae) associated with Aplysina cauliformis (Carter, 1882) (Porifera: Demospongiae) from Todos-os-Santos Bay, Northeastern Brazil, European Journal of Taxonomy 968, pp. 37-59 : 39-43

Spongiopsyllus athosi sp. nov.

urn:lsid:zoobank.org:act:BAE1A489-E87E-472E-9F14-3FA99AA596C7

Figs 1–2 , Tables 1 , 4

Diagnosis

Body shield-form dorso-ventrally flattened, pedigerous somite three and four not fused. Antennule 16-segmented, presenting fusions of segments (III–VI, IX–XIII, XXIII–XXVIII), and with aesthetasc on segment 14. Antenna with 4 spinules on outer, and 1 spinule on inner margins of exopod segment, and endopod 2-segmented with 2 long and 2 short apical setae. Maxillule with 3 setae on inner lobe, and 4 setae on outer lobe. Maxilliped with endopod 3-segmented, showing 2 setae on first segment, 1 on second and three on third; setal formula (2,1,1+claw).

Etymology

The tapered morphology of leg 1 third endopodal segments, showing sharpened processes, inspired the species name referring to the swordsman ‘Athos’, one of Alexandre Dumas’ characters from ‘ The Three Musketeers ’, a historical adventure novel written in 1844.

Material examined

Holotype

BRAZIL • ♀; Bahia, Todos-os-Santos Bay, Pedra Cardinal ; 12°50′15″ S, 38°32′58″ W; 20 May 2017; L.C.C. Silvany leg.; manually collected, associated with the sponge Aplysina cauliformis ( Carter, 1882) ; UFBA 3291 .

Description

Female

Body length (from cephalosome to the furcal rami) 1170 µm and greatest body width (cephalosome) 850 µm. Prosomal shield flattened ( Fig. 1A ), with radiating bands along outer margin. Pedigerous somites 2–4 free. Urosome ( Fig. 1B ) 4-segmented. Genital double-somite fused with fifth pedigerous somite, 150 µm long, and with length:width ratio 1.3:1. Three postgenital somites present, all wider than long, 80 ×67, 75 ×47, 65 ×32 µm, respectively. Prosome:urosome length ratio 1.5:1. Caudal rami elongate, 107 µm long, with setules along medial-distal inner margin, and armed with 6 setae distally.

Antennule ( Fig. 1C ) slender, 251 µm long (not including setae), and 16-segmented. Length of segments: 62, 22, 24, 10, 9, 13, 7, 10, 10, 12, 11, 11, 12, 14, 8 and 16 µm, respectively. Segmental homologies and setation as follows: I-1; II-2; III–VI-7; VII-2; VIII-2; IX–XIII-6; XIV-2; XV-2; XVI-2; XVII-1; XVIII-2; XIX-2; XX-2; XXI-1+ae; XXII-2; XXIII–XXVIII-8. All setae naked. Aesthetasc 102 µm long.

Antenna ( Fig. 1D ) 224 µm long (including distal claw); coxa 24 µm long; basis 76 µm long. Exopod 1-segmented, 65 µm long, with 2 long slender distal setae, and 5 small spinules along margins. Endopod 2-segmented; first segment 53 µm long, unarmed, with 7 spinules on outer margin; second segment 22 µm long, ornamented with row of setules along outer margin, and armed with 2 long and 2 short naked setae; distally curved claw (49 µm) with bump-like projection subdistally.

Oral cone 210 µm long, reaching first postgenital somite ( Fig. 1A ). Mandible comprising stylet and slender 2-segmented palp ( Fig. 1E ) measuring 40 and 62 µm long, respectively. Palp with second segment armed with 2 apical, plumose setae and ornamented with setules along outer margin. Stylet slender and pointed, 142 µm long.

Maxillule ( Fig. 1F ) bilobed; inner lobe 68 µm long, armed with 3 long apical setae. Outer lobe 49 µm long, armed with 4 short setae and ornamented with setules along outer margin; all setae naked.

Maxilla ( Fig. 1G ) with syncoxa and curved claw measuring 217 and 134 µm long, respectively; claw with soft bump-like projection subdistally.

Maxilliped ( Fig. 2A ) 5-segmented, 298 µm long (excluding claw); syncoxa 84 µm long, with inner seta and 3 setules on distal inner margin; basis 138 µm long, unarmed. Endopod 3-segmented, 22, 23, and 31 µm long, respectively; first segment with 2 naked unequal setae; second segment with distal small seta; third segment with small distal seta and curved claw measuring 56 µm long.

P1–P3 ( Fig. 2B–D ) biramous, with 3-segmented rami. P4 ( Fig. 2E ) with 3-segmented exopod and endopod absent. Armature formula reported in Table 1 .

First and second exopodal segments of P1 ( Fig. 2B ) with setules on outer margins; second segment with setules on inner margin; outer margin of third segment with spinules, inner margin naked. Second endopodal segment of P1 ( Fig. 2B ) with setules on outer margin and moderate sharpened process on distal margin. Third endopodal segment of P1 ( Fig. 2B ) prolonged distally into sharpened process, therefore distal setae located sub-distally on inner margin.

First and second exopodal segments of P2 ( Fig. 2C ) with outer margins naked, second exopodal segment of P2 with few setules on medial inner margin. Second endopodal segment of P2 ( Fig. 2C ) with spinules on outer margin and setules on inner margin; third endopodal segment with setules on proximal inner margin.

Basis of P2 and P3 with spinules on inner and outer margins, respectively.

P3 exopodal outer margins with spinules ( Fig. 2D ); first and second endopodal segments with setules on both margins; second endopodal segments with one small and one tiny sharpened process on distal margin; third endopodal segment with small sharpened process on distal margin.

P4 exopodal outer margin with spinules ( Fig. 2E ,), which are larger on second segment than on other segments; medial distal margins of first and second segments with two tiny, sharpened processes on medial distal margin.

Free exopodal segment of P5 ( Fig. 1B ) elongate, curved, 207 µm long, longer than genital double-somite, and armed with 2 distal and one outer medial plumose seta.

Male

Unknown.

Figures

Fig. 1. Spongiopsyllus athosi sp. nov., ♀, holotype (UFBA 3291). A. Habitus, dorsal view. B. Urosome. C. Antennule. D. Antenna. E. Mandibular palp. F. Maxillule. G. Maxilla. Scale bars: A = 200 µm; B–G = 50 µm.

Fig. 2. Spongiopsyllus athosi sp. nov., ♀, holotype (UFBA 3291). A. Maxilliped. B. L1. C. L2. D. L3. E. L4. Scale bars = 50 µm.