Cryptopontius pentadikos, Farias & Neves & Johnsson, 2020

Farias, Amilcar, Neves, Elizabeth G. & Johnsson, Rodrigo, 2020, Two new species of Cryptopontius Giesbrecht, 1899 (Copepoda, Siphonostomatoida Artotrogidae) associated with invertebrates from Northeastern Brazil, Zootaxa 4810 (3), pp. 481-494 : 487-492

publication ID	https://doi.org/ 10.11646/zootaxa.4810.3.5
persistent identifier	https://treatment.plazi.org/id/03D78781-172B-381C-FF63-FC4C99DDFDEA
treatment provided by	Plazi
scientific name	Cryptopontius pentadikos
status	sp. nov.

Treatment

Cryptopontius pentadikos sp. nov.

ZooBank under urn:lsid:zoobank.org:act:404642DE-81E5-4B4C-90BD-33CA417E4443

( Figures 5–8 View FIGURE 5 View FIGURE 6 View FIGURE 7 View FIGURE 8 )

Material examined. Holotype male ( UFBA 3332 ), allotype juvenile female ( UFBA 3333 ) and one paratype male ( UFBA 3334 ); Periperi Beach (12°51’59”S, 38°28’47”W), Salvador city, Bahia State, Brazil, collected by I. Bonfim and A. Farias on August 30, 2015. Specimens found associated with the sponge Clathria sp GoogleMaps . Holotype and allotype dissected and mounted on permanent slides, paratype preserved in ethanol 70%.

Description of male. Body ( Fig. 5A View FIGURE 5 ) cyclopiform, dorsoventrally flattened, 922 µm long, 465 µm wide. Cephalotorax nearly as long as wide, 459 µm long and 465 µm wide (length:width ratio = 1:0.9); epimera of cephalothorax, first and second pedigerous somites with slightly projected posterior corners. Prosome 611 µm long, longer than wide (length:width ratio = 1:0.7). Fourth pedigerous somite narrow and bow-shaped due to posterior corners highly projected and fifth pedigerous somite reduced. Urosome ( Fig. 5B View FIGURE 5 ) 365 µm long and 192 µm wide (length: width ratio = 1:0.5), composed of six somites. Genital somite 102 µm long and maximum width 192 µm, (length: width ratio = 0.5:1). Four postgenital somites all wider than long (124×44, 123×38, 102×37 and, 99× 52 µm, respectively). Prosome: urosome ratio = 1:0.6. Caudal rami ( Fig. 5B View FIGURE 5 ) nearly longer than wide, 50× 41 µm. Length: width ratio = 1:0.8, armed with six setae.

Antennule ( Fig. 5C View FIGURE 5 ) 266 µm long (not including setae), 11-segmented. Length of segments in proximal to distal order: 49, 13, 35, 11, 9, 10, 14, 9, 43, 21 and 52 µm respectively. Segmental homologies as follows: 1(I)-10; 2(II)-1+ae; 3(III–VI)-4+4ae; 4(VII)-1+ae; 5(VIII)-1; 6(IX–XII)-2+ae; 7(XIII)-1+1ae; 8(XIV)-1+ae; 9(XV–XVIII)- 3+4ae; 10(XIX–XX)-1+ae; 11(XXI–XXVIII)-11+ae. Terminal aesthetasc 134 µm long. Rounded spots on segments representing scars of missing setae in first segment, and aesthetascs on second, third and, fourth ones.

Antenna ( Fig. 5D View FIGURE 5 ) with basis 27 µm long. Exopod 1-segmented, 8 µm long, with two long naked apical setae. Endopod 2-segmented, first segment 19 µm long, unarmed; second segment 29 µm long, armed with naked seta on proximal inner margin and two long robust setae distally located, 37 and 30 µm long, longer one with denticles on inner margin.

Mandible ( Fig. 6A View FIGURE 6 ) comprising stylet 323 µm long, inserted into oral cone; oral cone reaching maxilliped basis. Mandibular stylet distally showing serrated region with small setules. Mandibular palp absent.

Maxillule ( Fig. 6B View FIGURE 6 ) bilobed, inner and outer lobes with 66 and 40 µm long, respectively. Inner lobe laterally naked, armed with two slender setae, both broken. Outer lobe ornamented with long setules on outer margin, two robust setae distally, 34 and 46 µm long respectively, both setae armed with small setules on outer margin, longer seta armed with strong and sparse denticles. Maxilla ( Fig. 6C View FIGURE 6 ) with unarmed syncoxa, 166 µm long, and claw, 205 µm long; claw with subdistal naked seta, protrusions on outer margin and tip bent forming 90-degree angle.

Maxilliped ( Fig. 6D View FIGURE 6 ) 3-segmented, 368 µm long; basis 192 µm long, unarmed. Endopod 2-segmented, measuring 17 and 39 µm long respectively and curved claw-like element, 89 µm long. First and second endopodal segments with naked seta distally on each segment.

Legs 1−3 ( Figs. 7 View FIGURE 7 A−D) biramous, with 3-segmented rami, leg 4 with exopod 3-segmented and endopod absent. Armature formula as follows:

Leg 3 ( Fig. 7C View FIGURE 7 ) showing coxa with row of long setules on outer margin and long plumose seta on inner margin. Additionally, leg 3 showing seta much smaller than distal spine on third endopodal segment. Leg 4 ( Fig. 7D View FIGURE 7 ) showing minute plumose setae on inner margin of coxa, small naked seta on outer margin of basis and long distal spine on the third exopodal segment. Leg 5 ( Fig. 4E View FIGURE 4 ) with basal seta located in the protopodal segment fused to somite, exopodal segment longer than wide, 4× 2 µm, with lateral seta and two distally located setae. Leg 6 located midventrally, with three naked setae.

Juvenile Female. Body ( Fig. 8A View FIGURE 8 ) cyclopiform, dorsoventrally flattened, length (excluding caudal setae) 658 µm and body width 293 µm. Prosome longer than wide 486× 297 µm. Length:width ratio = 1:0.6. Epimera of cephalothorax, first and second pedigerous somite with slightly projected posterior corners as in male. Fourth pedigerous somite slightly less projected and bow-shaped as in male, fifth pedigerous somite reduced. Urosome ( Fig. 8B View FIGURE 8 ), 172 µm long, composed of five somites. Genital double-somite 41 µm long and maximum width 101 µm, length:width ratio = 0.4:1. Three postgenital somites wider than long (18×79, 27×71 and, 32× 72 µm respectively). Caudal rami ( Fig. 8B View FIGURE 8 ) longer than wide, 33× 28 µm. Length:width ratio 1:0.8, armed with six setae. Antennule, antenna and oral appendages broken. Leg 5 ( Fig. 8B View FIGURE 8 ) with protopodal segment fused to somite, basal seta broken, rudimentary free exopodal segment, as wide as long with 2 distal naked setae. Other legs as in male.

Etymology. The specific name “ pentadikos ”, from the Greek meaning “five”, alludes to the proximal region of the antennule, in which there are five segments, resulting from the fusion of ancestral segments III to VI.

Remarks. Although most of the Cryptopontius species have been described based on female individuals, there are some artotrogid species descriptions based in male specimens such as Bradypontius ovatus Nicholls, 1944 , Artotrogus latifurcatus Nicholls, 1944 , Tardotrogus challengeri Eiselt, 1961 , Antarctopontius spinipes Eiselt, 1965 , Bradypontius ancistronus Neves & Johnsson, 2008 , and C. aesthetascus Neves & Johnsson, 2008 ( Nicholls 1944; Eiselt 1961; 1965; Neves & Johnsson 2008). Moreover, as pointed out by Neves & Johnsson (2008), non-sexually dimorphic features can distinguish male from female specimens, which means all characteristics except general aspects of body, urosome and distal antennule segmentation (XIII to XXVIII).

Cryptopontius pentadikos sp. nov. shows a uniramous fourth leg with nine elements on the third exopodal segment, 2 and 6 setae on the second and third endopodal segment of leg 1, respectively. The new species shares these features with C. paracapitalis Nicholls, 1944 , C. madeirensis Johnsson, 2001 , C. tanacredii Johnsson, Rocha & Boyko, 2002 , C. graciloides Ummerkutty, 1961 , C. ascidius Kim, 1996 , C. aesthetascus , C. brevifurcatus ( Giesbrecht, 1895) , C. brevicaudatus (Brady, 1910) , C. expletus Neves & Johnsson, 2008 and C. phyllogorgius sp. nov. However, C. pentadikos sp. nov. can be distinguished from all these species by having ancestral segments III-VI fused and five expressed antennulary segments, rather than three as in [fc] Cryptopontius phyllogorgius . sp. nov., C. graciloides , C. madeirensis , C. expletus and C. tanacredii , four as in C. paracapitalis , C. brevicaudatus , C. brevifurcatus and C. ascidius and seven in C. aesthetascus proximal to fused ancestral segments IX-XII ( Nicholls 1944; Ummerkutty 1961; Kim 1996; Johnsson 2001; Johnsson et al. 2002; Neves & Johnsson 2008).

Moreover, C. pentadikos sp. nov. differs from C. brevifurcatus and C. ascidius by having maxillule outer lobe with 2 setae instead of 3 ( Giesbrecht 1895; Kim 1996); from C. paracapitalis by having maxillule inner lobe with two setae instead of 1 ( Nicholls 1944), or from C. brevicaudatus and C. madeirensis that have 3 setae on inner lobe ( Giesbrecht 1895; Johnsson 2001); from C. tanacredii by having maxillule inner lobe with similar length to outer lobe ( Johnsson et al. 2002) and from C gracilioides that has a single terminal seta on the antennal exopod ( Ummerkutty 1961), instead of two as in the new species.

Cryptopontius pentadikos sp nov. and C. phyllogorgius sp nov. differ from the others Brazilians species by having 11 and 9 antennulary segments, respectively, instead of 12 on C. aesthetascus and 8 in C. expletus . Also, C. aesthetascus and C. expletus show 3 apical setae, instead of 2 apical and a single basal seta on the second segment of antennal endopod. C. aesthetascus has a 3-segmented maxilliped endopod, character absent in all Brazilian species, that have 2 segments.