Cryptopontius phyllogorgius, 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 : 482-487

Cryptopontius phyllogorgius sp. nov.

ZooBank under urn:lsid:zoobank.org:act:7072200F-E08A-4659-BCDC-0C4B4AE3ACED

( Figures 2–4 )

Material examined. Holotype female ( UFBA 3331 ), 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 gorgonian Phyllogorgia dilatata (Esper 1806) . Holotype dissected and mounted on slide.

Description of female. Body ( Fig. 2A ) cyclopiform, dorsoventrally flattened, 1.107 µm long, 584 µm wide. Cephalothorax 584 long and 769 µm wide (length:width ratio = 0.7:1); with greatest width at posterior quarter; epimera of cephalothorax and first pedigerous somite with slightly projected posterior corners. Prosome 784 µm long and 769 µm wide, nearly as wide as long, (length: width ratio = 1:0.9). Epimera of fourth pedigerous somite not visible in dorsal view and extended to anterior a quarter of genital double-somite. Urosome ( Fig. 2B ) 251 µm long and 184 µm wide (length: width ratio = 1:0.7), composed of five somites. Genital double-somite 109 µm long and maximum width 184 µm, length: width ratio = 0.6:1. Two postgenital somites, both wider than long (82 × 21 and 76 × 24 µm, respectively), anal somite nearly as long as two postgenital somites (84,4 × 51,5 um). Caudal rami nearly as long as wide (37 × 34), length: width ratio = 1:0.9, armed with six setae.

Antennule ( Fig. 2C ) 271 µm long (not including setae), 9-segmented. Lengths of segments in proximal to distal order: 49, 14, 57, 24, 15, 23, 20, 21 and 48 µm respectively. Segmental homologies and setation as follows: 1(I)-1; 2(II)-2; 3(III–VIII)11; 4(IX–XII)-7; 5(XIII–XIV)-1+I; 6(XV–XVI)-1; 7(XVII–XVIII)-1; 8(XIX–XX)-1; 9(XXI– XXVIII)-11+Aesthetasc. Segment 2 with long seta showing robust basis; a spine on segment 5 and very slender and long seta on terminal segment. Aesthetasc 79 µm long.

Antenna ( Fig. 2D ) with coxa 11 µm long; basis 34 µm long. Exopod 1-segmented, 6 µm long, with two distal naked setae. Endopod 2-segmented, first segment 21 µm long, unarmed; second segment 27 µm long, armed with short subproximal, 19 µm long, located at about half of the segment and two distal setae, a short one and a robust long spine-like seta, both 27 and 61 µm long respectively. All endopodal setae plumose.

Oral cone ( Fig. 3A ) 503 µm long, reaching insertion of leg 1. Mandible ( Fig. 3B ) comprising stylet inserted into oral cone, distal margin armed with few denticles.

Mandibular palp absent.

Maxillule ( Fig. 3C ) bilobed; inner and outer lobes measuring 73 and 63 µm long, respectively. Each lobe armed with two distal setae. Inner lobe tapering, armed with long plumose seta and short naked seta, 36 and 14 µm long, respectively. Outer lobe armed with two strong setae, 63 and 46 µm long, respectively; longer seta armed with large sparse spinules on inner margin; outer lobe armed with row of long setules on outer margin. Maxilla ( Fig. 3D ) 506 µm long; unarmed syncoxa, 238 µm long and thin claw strongly curved distally towards outer margin and armed distally with naked seta.

Maxilliped ( Fig. 3E ) 4-segmented, 376 µm long; syncoxa unarmed, 34 µm long; basis longest, 144 µm long, with seta on medial inner margin. Endopod 2-segmented, measuring 62 and 46 µm long, respectively. First segment with naked seta distally; second segment with naked spine-like seta close to curved claw-like element, 90 µm long.

Legs 1−3 ( Figs. 4 A−C), biramous, with 3-segmented rami. Leg 4 ( Fig. 4D ) with 3-segmented exopod, and endopod absent. Armature formula as follows:

Coxa and basis of first leg ( Fig. 4A ) with short plumose setae. Legs 2 and 3 ( Figs. 4B and 4C ) with outer margin of exopod with spinules and outer margin of endopod showing setules, except the first endopod of leg 3. Leg 3 ( Fig. 4C ) with row of short setules on outer margin of coxa and slender naked seta on outer margin of basis. Legs 2–3 showing long, robust spine distally on third exopodal and endopodal segments. Legs 1–3 with two tooth-like processes on distal outer margin of second endopodal segment. Fifth leg ( Fig. 2B ) has a protopodal segment fused to somite, and a free reduced exopodal segment, nearly as wide as long, with 3 distal naked setae. Leg 6 located midlaterally with single seta.

Male: Unknown

Etymology. The specific name refers to the host species, Phyllogorgia dilatata (Esper, 1806) .

Remarks. Among other features, Cryptopontius can be distinguished from the others genera of Artotrogidae by having both rami of first leg 3-segmented, with 3 spines and 4 or 5 setae (III, 4/5) on third exopodal segment; leg 4 uniramous, lacking endopod, or represented by a single seta on a minute segment ( Boxshall & Halsey 2004).

The new species shares a 9-segmented antennule with another 12 species of the genus. However, this pattern can be achieved in two different ways in the genus. The first pattern occurs with the ancestral segment II free and the segments III-VIII fused, as can be observed in six species: C. tenuis ( Giesbrecht, 1895) , C. gracilis Wilson, 1932 , C. orientalis Ummerkutty, 1961 , C. graciloides Ummerkutty, 1961 , C. paracapitalis Nicholls in Eiselt, 1961 and C. tanacredii Johnsson, Rocha & Boyko, 2002 ( Giesbrecht 1895; Wilson 1932; Ummerkutty 1961; Eiselt 1961; Johnsson et al. 2002). The second pattern shows the fusion of ancestral segments II-VII and the segment VIII free, as seen in the remaining six species: C. brevifurcatus ( Giesbrecht, 1895) , C. brevicaudatus ( Brady, 1899) , C. longipes Nicholls, 1944 , C. proximus Nicholls, 1944 , C. madeirensis Johnsson, 2001 and C. acutus Kim, 2007 ( Giesbrecht 1895; Brady 1899; Nicholls 1944; Johnsson 2001 and Kim 2007). Cryptopontius phyllogorgius sp. nov. shows the identical fusion pattern of the second group of species.

Cryptopontius phyllogorgius sp. nov. differs from C. longipes and C. acutus in having nine elements on the third exopodal segment of leg 4 ( Nicholls 1944; Kim 2007) instead of eight. The new species can be distinguished from C. proximus , C. gracilis , C. tenuis and C. orientalis by having two setae on the second endopodal segment of P1 instead of one ( Giesbrecht 1895; Wilson 1932; Nicholls 1944; Ummerkutty 1961).

The maxillule outer lobe of C. brevifurcatus has three setae ( Brady 1899), whereas the new species has only two. In addition, Cryptopontius phyllogorgius sp. nov. has two setae on the inner lobe of the maxillule, distinct from C. brevicaudatus and C. madeirensis which have three setae ( Brady 1899; Johnsson 2001) and C. paracapitalis with only one seta ( Eiselt 1961). C. tanacredii and C. graciloides also have two setae on the inner lobe, but, in C. tanacredii the inner lobe is remarkable longer than the outer one and C. graciloides has a single seta on the antennal exopod ( Ummerkutty 1961; Johnsson et al. 2002).

Figures

FIGURE 2. Cryptopontius phyllogorgius sp. nov. female (holotype: UFBA 3331). A, body, dorsal view; B, urosome; C, antennule; D, antenna. Scale bars: A = 200 µm; B = 100 µm; C–D = 50 µm.

FIGURE 3. Cryptopontius phyllogorgius sp. nov. female (holotype: UFBA 3331). A, oral cone; B, mandible; C, maxillule; D, maxilla; E, maxilliped. Scale bars: A = 200 µm; B = 25 µm; C–E = 50 µm.

FIGURE 4. Cryptopontius phyllogorgius sp. nov. female (holotype: UFBA 3331). A, leg 1; B, leg 2; C, leg 3; D, leg 4; E, leg 5. Scale bars: A–E = 50 µm.