Kuayguara, Farias & Neves & Johnsson, 2025

Order Siphonostomatoida Burmeister, 1835 View in CoL Family Artotrogidae Brady, 1880

Kuayguara gen. nov. urn:lsid:zoobank.org:act:

Diagnosis: Artotrogidae . Body cyclopiform, dorso-ventrally flattened. Cephalic shield ornamented with scale-like structures showing integumental organs. Prominent dorsal crest and rostrum. Radial bands on the lateral margins of the cephalosome. Epimera of the cephalosome, second, and third pedigerous somites projected posteriorly. Medio-posterior margin of the second and third pedigerous somites with posteriorly elevated projections medially aligned. Urosome 5-segmented on female, genital double-somite with two pairs of produced posteriorly projected epimera. Male urosome 6-segmented, genital somite and first post-genital somite with a pair of projected epimera produced posteriorly. Both female and male with paired genital apertures, equal sized and ventrally located. Female antennule 8-segmented. Male antennule 9-segmented, with additional aesthetascs, showing an incomplete segmentation on the terminal segment; and significantly large spine on segment 7. Antennal exopod represented by seta, and 2-segmented endopod. Maxillule bilobed. Maxilliped 5-segmented. Leg 1 uncommonly reduced, with single-segmented ramus. Leg 1, 3, and 4 with coxa and basis fused. Leg 2 and 3 biramous and 3-segmented. Leg 4 lacking endopod.

Type species: Kuayguara etymatee sp. nov. by original designation.

Etymology: The genus name Kuayguara is a junction of the words “ Kûa ” (= bay) and “- ygûara ” (= inhabitant), from old-Tupi language, referring to the Tupinambá people, the ethnic group that inhabited Todos-os-Santos Bay before the arrival of the Portuguese colonizers.

Remarks: When redefining Artotrogidae, Eiselt (1961) described, among other characteristics, the legs 1 to 4 as being: “ normal ausgebildet oder in verschiedenem Ausbasse reduziert, P4 bis zu seinem völligen Fehlen ”, (normally developed or reduced to various degrees, leg 4 to its complete absence). In fact, the different levels of reduction patterns of leg 4 on Artotrogidae performed an important role in the differentiation of the genera, splitting the family in a few groups: (1) Leg 4 biramous with 3-segmented exopod and endopod ( Abyssopontius Stock, 1985 ; Antarctopontius Eiselt, 1965 ; Artogordion Ivanenko, Bandera and Conradi, 2018 ; Bradypontius Giesbrecht, 1895 ; Cribropontius Giesbrecht, 1899 ; Glannapontius Holmes, 1998 ; Myzopontius Giesbrecht, 1895 ; Neobradypontius Eiselt, 1961 , Neopontius Scott T., 1898 ; and; Sestropontius Giesbrecht, 1899 ). (2) Leg 4 biramous with 3-segmented exopod and 2-segmented endopod ( Arctopontius Sars G.O., 1915 and Metapontius Hansen, 1923 ). (3) Leg 4 with 3-segmented exopod, without endopod ( Ascidipontius Kim IH, 1996 ; Chejupontius Lee J and Kim IH, 2023 ; Cryptopontius Giesbrecht, 1899 ; Dyspontius Thorell, 1859 ; Pteropontius Giesbrecht, 1895 ; Pulicitrogus Kim I.H., 1998 ; and; Sewellopontius Ummerkutty, 1966 ). (4) Leg 4 reduced to a protopod ( Pseudotrogus Eiselt, 1961 ). (5) Leg 4 absent ( Glyptotrogus McKinnon, 1988 ; Artotrogus Boeck, 1859 ; and; Tardotrogus Eiselt, 1961 ).

Kuayguara View in CoL gen. nov. shares the uniramous leg 4 with a 3-segmented exopod with the 7 genera included in the third group, but these taxa can be easily differentiated by the level of reduction patterns found on their leg 1: Ascidipontius View in CoL , Chejupontius View in CoL , Cryptopontius View in CoL , Dyspontius View in CoL , and Pulicitrogus View in CoL exhibit a biramous 3-segmented leg 1, with the exopod formula: (I-0, 0-0; II, 3), (I-0; 0-1; II, I, 2 or II, I, 1), (I-1; I-1; III, 4 or III, 5), (I-1; I-1 or 0-1; II, 5 or II,4), (I-0; 0-1; II, 3), respectively, characterizing minor modifications in the pattern, showing only a few elemental reductions ( Thorell 1859; Giesbrecht 1899; Sars 1918; Kim 1996 1998 2016; Johnsson 2001; Farias et al. 2021; Lee and Kim 2023). This is completely different from Kuayguara View in CoL gen. nov. which shows only one-segmented ramus on leg 1.

Sewellopontius species can exhibit a moderate reduction pattern, with leg 1 exopod 2- or 3-segmented, with the formula (I-0 or 0-0; 0-1; II, 3) or (I-0; II, 3 or II, 4) ( Ummerkutty 1966; Kim 1996; Lee and Kim 2023). Therefore, also differing from the one-segmented ramus of leg 1 in the new genus.

The species included in the genus Pteropontius View in CoL exhibited the most reduced pattern known to the leg 1, with both exopod and endopod 2-segmented, with the formula (0-1 or I-0; II, 3 or II, 4). This pattern has been confirmed with the recent redescription of the type species by Lee and Kim (2023) and differentiates it from the new genus.

The species P. pediculus exhibits an exception to this pattern, it was described based on a single male specimen found in association with the coral Echinopora lamellosa (Esper, 1791) on Mauritius Is., Stock (1966) also classified the specimen as “somewhat aberrant”, alluding to the uncommon morphology of its reduced first leg, which exhibit a single segmented ramus.

Considering the erection of the new genus, it is possible to observe other differences between P. pediculus from all other Pteropontius species, such as the 2-segmented antennal endopod (instead of 1-segmented); leg 1 and leg 3 with coxa and basis fused (instead of articulated). Thus, since these characteristics previously mentioned, plus the leg morphology, are diagnostic of the new genus, P. pediculus should be moved to Kuayguara gen. nov., with a new combination as Kuayguara pediculus ( Stock, 1966) comb. nov.

Kuayguara etymatee gen. et sp. nov. ( Figs. 2–5 View Fig View Fig View Fig View Fig ) urn:lsid:zoobank.org:act:

Material examined: Holotype ñ ( UFBA4130 ), dissected on permanent slide; allotype ò ( UFBA4133 ), dissected on permanent slide; from mixed benthonic samples, collected at public pier on Barra do Paraguaçu beach ( Salinas da Margarida city – 12°50'25.0"S, 38°47'40.9"W) GoogleMaps . Paratypes: 1ò (UFBA4131) and, 1ñ (UFBA4132) collected at public pier on Barra do Paraguaçu beach (Salinas da Margarida city – 12°50'25.0"S, 38°47'40.9"W). 1ñ (UFBA4092) and, 1ñ (UFBA4093) collected at Marina de Itaparica pier, Itaparica Is. (Itaparica city – 12°53'21.2"S, 38°41'04.2"W). 1ñ (UFBA4112) collected at a private pier on Bom Jesus dos Passos Is. ( Salvador city – 12°45'42.4"S, 38°38'09.5"W). 1ò (UFBA4098), 1ñ (UFBA4099), 1ò (UFBA4100), 1ñ (UFBA4101), 1ñ (UFBA 4102), 1ñ (UFBA 4103), and 2ñ (UFBA4134), collected at Estação de Medidas Magnéticas de Itaparica pier, Itaparica Is. (Itaparica city – 12°52'47.9"S, 38°41'10.1"W). 1ò (UFBA4137) and 1ò (UFBA4138), collected at a private pier on Bimbarras Is. (Madre de Deus city – 12°43'36.1"S, 38°38'02.7"W). 3ñ (UFBA4316), 1ò (UFBA4317), 2ñ and 1ò (UFBA4139), 2ñ (UFBA4187), 1ñ (UFBA4353), 1ñ (UFBA4827), 4ñ (UFBA4826), and 1ò (UFBA4827) collected at a private pier on Madre de Deus Is. (Madre de Deus city – 12°43'58.8"S, 38°37'22.8"W). 1ñ (UFBA4777), 1ñ (4778), and a juvenile (UFBA4779) collected at a public pier on Bom Jesus dos Passos Is. ( Salvador city – 12°45'20.7"S, 38°38'21.5"W). All paratypes from mixed benthonic samples, preserved in ethanol.

Description of the female holotype: Body ( Fig. 5a View Fig ) cyclopiform, dorso-ventrally flattened, 888 µm long. Cephalic shield adorned with scale-like structures showing sensilla on each integumental organs ( Fig. 5a, b View Fig ), and radial bands along all margins ( Fig. 2b View Fig ); body length: width ratio 1.6:1. Cephalosome slightly wider than long (539 × 553 µm); with robust dorsal crest, ranging from posterior medial margin to prominent rostrum; also bearing radial bands along margins and ending in projected epimera. Second and third pedigerous somites with serrulated margins, and showing medial posterior margins with dorsal elevated projections aligned with dorsal crest. Second pedigerous somite significantly wider than long (88 × 327 µm), with produced projected epimera. Third pedigerous somite wider than long (100 × 287 µm), with elevated structure on posterior medial margin projecting over fifth pedigerous somite. Fourth pedigerous somite twice as wide as long (31 × 62 µm), and strongly reduced. Prosome longer than wide (703 × 553 µm), prosome: urosome length ratio 1.2:1.

Urosome ( Fig. 2c View Fig ) 5-segmented, longer than wide (245 × 212 µm). Fifth pedigerous somite wider than fourth one (30 × 96 µm). Genital double-somite nearly twice as wide as long (110 × 214 µm) exhibiting two pairs of projected epimera. Paired genital apertures on the proximal region of the somite, equal sized, wellspaced and ventrally located. Egg sac not observed. First and second post-genital somites wider than long (28 × 78 µm, and 19 × 56 µm). First somite partially covered by genital one. Robust anal somite, wider than long (42 × 77 µm), showing row of five parallel perforations. Caudal rami longer than wide (49 × 28 µm), armed with two smooth and small dorsal setae, and distally armed with 4 setae. Caudal rami length: width ratio 1.7:1.

Antennule ( Fig. 2d View Fig ) 8-segmented, total length measuring 249 µm long. Length measurements made along medial margin = 51, 63, 25, 18, 20, 12, 19, and, 41 µm long, respectively. Segmental homologies and armature as follow: I – 1; II-VIII – 6; IX-XII – 4; XIII-XIV – 1+s; XV-XVI – 1; XVII-XVIII – 1; XIX-XX – 1; XXI-XXVIII – 10+ae. All setae naked, two distal long setae almost as long as aesthetasc, which is 93 µm long.

Antenna ( Fig. 2e View Fig ) 4-segmented, total length measuring 100 µm long (without distal setae), Coxa and basis unarmed, 10 and 35 µm long, respectively. Exopod reduced to seta, 22 µm long, almost as long as first endopodal segment. Endopod 2-segmented, first segment 25 µm long and unarmed, second segment 30 µm long, 1.2 times longer than first one, armed medially with plumose seta, and distally with 3 setae: a small slender seta, 2 stout ones, unequally sized, and elongated plumose seta.

Oral cone ( Fig. 2a View Fig ) 260 µm long, reaching basis of maxilliped. Mandible with long stylet inserted in oral cone, showing 4 teeth-like projections at the tip, palp absent ( Fig. 2f View Fig ).

Maxillule ( Fig. 2g View Fig ) bilobed, inner lobe longer than outer one, 109 µm long (broken, as long as the oral cone on paratypes), exhibiting a tapering shape and naked margins, with long plumose seta; outer lobe 55 µm long, with row of setules on outer margin, and two strong distal setae; longest seta has plumose inner margin and spinules along outer margin, shortest one shows spinules on inner margin and naked outer margin.

Maxilla ( Fig. 3a View Fig ) stout, syncoxa naked, measuring 202 µm long, with prominent bump on outer margin; (detached) strong basis (claw), 230 µm long, remarkably recurved, and armed with small stout seta on medio-distal margin. Maxilliped ( Fig. 3b View Fig ) 5-segmented, total length 291 µm long (not including distal claw); coxa 36 µm long, armed with single seta on inner margin, and row of setules on outer margin; basis unarmed, 136 µm long. Endopod 3-segmented, first segment unarmed, 28 µm long; second segment 38 µm long, armed with distal inner seta; third segment 53 µm long, armed with robust seta and terminal claw. Terminal curved claw measuring 82 µm long.

Leg 1 ( Fig. 3c View Fig ) showing no segmentation between coxa and basis, forming protopod, and exhibiting long seta on distal outer margin. Leg 1 ( Fig. 3c View Fig ) has a single-segmented ramus, armed with 3 distal unequal-sized setae.

Leg 1 to 4 armature formula as follows:

Outer margins of exopodal segments of legs 2 to 4 ( Fig. 3d–f View Fig ) armed with spinules. Endopodal segments of leg 2 ( Fig. 3d View Fig ) showing setules along outer margin. Third endopodal segment of leg 3 ( Fig. 3e View Fig ) exhibiting strong distal spine. Distal spine of the third exopodal segment of legs 3 and 4 ( Fig. 3e–f View Fig ) slightly bending on the proximal region.

Both protopod and exopod of leg 5 ( Fig. 3g View Fig ) extremely reduced, represented by 1 and 2 setae, respectively.

Description of the male allotype: Body ( Fig. 4a View Fig ) cyclopiform, longer than wide, smaller but comparatively slightly slender than female (530 × 292 µm), body length: width ratio 1.8:1. Body adorned as seen on female ( Fig. 6a, b View Fig ). Cephalosome longer than wide (319 × 292 µm), cephalosome length: width ratio: 1.1:1. Prosome longer than wide (402 × 292 µm), prosome: urosome length ratio 2.5:1. Urosome 6-segmented, longer than wide (158 × 110 µm). Genital somite ( Fig. 4b View Fig ) wider than long (63 × 148 µm), with only a pair of epimera posteriorly projected. Paired genital apertures, well-developed, equal-sized, and ventrally located. First post-genital somite almost as wide as genital somite (35 × 123 µm), also showing epimera posteriorly projected. Second post-genital somite almost entirely covered by first one, and followed by third somite, both wider than long (17 × 63 µm and 13 × 48 µm), respectively. Anal somite robust, almost twice wider than long (36 × 63 µm). Caudal rami longer than wide (31 × 22 µm), bearing two dorsal small naked setae and four terminal setae, caudal rami length: width ratio 1.4:1.

Antennule ( Fig. 4c View Fig ) 9-segmented, total length along medial margin measuring 312 µm long. Segments measurements: 31, 60, 12, 15, 35, 23, 49, 27, and, 60 µm long, respectively. Segmental homologies as follows: I – 0; II-VI – 3+5ae; VII – 1+ae; VIII – 0; IX-XII – 2+s+3ae; XIII-XIV – 1+ae; XV-XVIII – 3+s+ae; XIX-XX – 1+ae; XXI-XXVIII – 9+ae. All setae naked. Large spine on segment XV-XVIII measuring 46 µm long, almost reaching proximal margin of the last segment. Terminal aesthetasc measuring 147 µm long.

Maxilla ( Fig. 4d View Fig ) with unarmed syncoxa, 179 µm long, narrower than in female; and strong basis (grasping claw) 208 µm long, armed with small stout seta on medio-distal margin.

First leg ( Fig. 4e View Fig ) sharing female uncommon reduced morphology. Protopodal segment bulkier (65 µm long × 49 µm wide), exhibiting small seta on distal inner margin in addition to long seta on distal outer margin. And finally, third leg ( Fig. 4f View Fig ) showing small distal seta on third exopodal segment.

All other features as seen on female.

Etymology: The species name etymatee is a junction on the words “ etymã ” (= leg) plus “ teé ” (= very different), both from old-Tupi language, alluding to the uncommon morphology of leg 1 of the new species.

Remarks: The only congener of the new species, Kuayguara pediculus ( Stock, 1966) comb. nov., was described based on a male, and some sexual dimorphic features can only be compared with the male of the new species ( Table 2). The male body from both species is similar, Kuayguara etymatee gen. et sp. nov. differs from K. pediculus comb. nov. based on features such as the circular-shaped radial bands on the lateral margins of the cephalosome (instead of elongated); the medio-posterior projection of the third pedigerous somite not only covering the fifth but also covering the proximal part of the genital somite (instead of not reaching the genital somite); and finally, the second post-genital somite not exhibiting posteriorly projected epimera (instead of the projected epimera observed on K. pediculus comb. nov. ( Stock 1966).

The antennule of the new species exhibits no aesthetasc on segment 4, three on segment 5, none on segment 7; and the terminal aesthetasc is only twice thicker than the others. While the male antennule of K. pediculus comb. nov. shows an aesthetasc on segment 4, two on segment 5, two on segment 7; and the terminal aesthetasc is 4 times thicker than the others ( Stock 1966).

The antenna Kuayguara etymatee gen. et sp. nov. exhibits a naked exopodal seta, and unadorned endopodal margins. While the male antenna of K. pediculus comb. nov. shows features not seen in the new species, such as a plumose exopodal seta, a row of setules on the first endopodal segment, and the crest-like structures on the inner margin of the first and second endopodal segments ( Stock 1966).

The maxillule of K. pediculus comb. nov. shows a row of setules on the proximal inner margin, and a minute lateral seta on the distal margin of the inner lobe ( Stock 1966); both features not observed in the new species.

The maxilla basis (grasping claw) of Kuayguara etymatee gen. et sp. nov. exhibits only one stout seta; while K. pediculus comb. nov. shows 3 spine-like projections and a row of denticles ( Stock 1966).

The maxilliped of the new species shows a naked seta on the first segment, a smooth second segment, and endopodal armature formula (0, 1, 1); while K. pediculus comb. nov. shows a plumose basal inner seta on the first segment; two rows of long setules, and a medial serrated spine on the second segment; and endopodal armature formula (2, 1, 1) ( Stock 1966).

Despite sharing the uncommon morphology of the legs, such as the reduction of the first, and the fusion of the coxa and basis on the third and fourth legs; Kuayguara etymatee gen. et sp. nov. exhibits a few more differences to point out from K. pediculus comb. nov.: on the first leg, the single-segmented ramus shows smooth margins (instead of row of setules on outer margins); the armature formula of the third endopodal segment of leg 3 is (1, 1+I, 3) (instead of (1, 2, 3)); and the fifth leg exopod is represented by 2 (instead of 3) terminal setae ( Stock 1966).

Key to Artotrogidae View in CoL genera (adapted from Boxshall and Halsey 2004)

1. L4 biramous ................................................................................ 2

- L4 uniramous, represented by protopod, or absent .................. 13

2. Epimeral plates of third pedigerous somite not produced beyond anterior margin of genital double-somite ................................... 3

- Epimeral plates of third pedigerous somite produced with posterolateral lobes extending posteriorly to anterior margin of double-somite ............................................................................. 9

3. Female antennule 14-segmented; leg 4 endopod 2-segmented ..... ............................................................ Metapontius Hansen, 1923 View in CoL

- Female antennule 9 to 14-segmented; leg 4 endopod 3-segmented ..................................................................................................... 4

4. Leg 5 reduced to single seta; antennary exopod absent, unarmed ............................................................ Abyssopontius Stock, 1985 View in CoL

- Leg 5 with at least 1 free segment (exopod) bearing 3 to 5 setae; antennary exopod with free segment bearing 2 setae or without free segment and represented by 2 setae .................................... 5

5. Antennary exopod 1-segmented ................................................. 6

- Antennary exopodal segment not expressed, represented by 2 setae on basis ................................. Glannapontius Holmes, 1998 View in CoL

6. Antennary exopod 1-segmented, armed with 3 setae; leg 5 armed with 2 tooth-like processes ............................................................ ........................ Artogordion Ivanenko, Bandera & Conradi, 2018 View in CoL

- Antennary exopod 1-segmented, armed with 2 setae; leg 5 without tooth-like processes ....................................................... 7

7. Leg 5 with free segment bearing 5 setae; antennary exopod with 2 setae ............................................. Antarctopontius Eiselt, 1965 View in CoL

- Leg 5 with free segment bearing 3 setae; antennary exopod with 2 setae ......................................................................................... 8

8. Oral cone with long distal siphon; maxillule outer lobe longer than inner lobe ............................. Myzopontius Giesbrecht, 1895 View in CoL

- Oral cone short, pear-shaped, without siphon; maxillule outer lobe shorter than inner lobe .................. Neopontius Scott T, 1898 View in CoL

9. Epimeral plates of third pedigerous somite reaching mid-region of genital double-somite ........................................................... 10

- Epimeral plates of third pedigerous somite extending beyond genital double-somite and reaching second free abdominal somite ........................................................ Neobradypontius Eiselt, 1961 View in CoL

10. Endopod and exopod of leg 4 with similar length ........................ ..................................................... Sestropontius Giesbrecht, 1899 View in CoL

- Endopod of leg 4 shorter than exopod ..................................... 11

11. Posterolateral angle of dorsal cephalic shield bifid ....................... .................................................... Cribropontius Giesbrecht, 1899 View in CoL

- Posterolateral angle of dorsal cephalic shield simple ............... 12

12. Leg 1 with 3 outer spines on exopodal segment 3; leg 4 with 3-segmented endopod ................. Bradypontius Giesbrecht, 1895 View in CoL

- Leg 1 with 2 outer spines on exopodal segment 3; leg 4 with 2-segmented endopod ...................... Arctopontius Sars GO, 1915 View in CoL

13. Leg 4 absent ............................................................................. 21

- Leg 4 present ............................................................................ 14

14. Leg 4 reduced to protopod bearing 1 or 2 setae on process at outer distal angle ................................ Pseudotrogus Eiselt, 1961 View in CoL

- Leg 4 uniramous, lacking endopod (or rarely biramous with endopod represented by a single seta on minute segment as seen in Cryptopontius digitatus Kim IH, 1996 View in CoL ) ............................... 15

15. Leg 1 showing some level of segmentation reduction ............. 16

- Both rami of leg 1 3-segmented ............................................... 18

16. Leg 1 biramous .......................................................................... 17

- Leg 1 uniramous, exopod 1-segmented ....... Kuayguara View in CoL gen. nov.

17. Both rami of leg 1 2-segmented .................................................... ...................................................... Pteropontius Giesbrecht, 1895 View in CoL

- Exopod of leg 1 2- or 3-segmented, endopod 3-segmented .......... ................................................ Sewellopontius Ummerkutty, 1966 View in CoL

18. Leg 1 with 3 outer spines and 4 or 5 setae (III,4/5) on third exopodal segment ...................... Cryptopontius Giesbrecht, 1899 View in CoL

- Leg 1 with 2 outer spines on third exopodal segment .............. 19

19. Leg 1 with 2 inner setae on second endopodal segment .......... 20

- Leg 1 with 1 inner seta on second endopodal segment ............ 21

20. Leg 1 with 2 spines and 4 setae (II,4) on third exopodal segment ............................................................... Dyspontius Thorell, 1859 View in CoL

- Leg 1 with 2 spines and 3 setae (II, 3) on third exopodal segment ............................................................ Pulicitrogus Kim IH, 1998 View in CoL

21. Second exopodal segment of leg 1 unarmed ................................. .......................................................... Ascidipontius Kim IH, 1996 View in CoL

- Second exopodal segment of leg 1 armed with inner seta ............ ............................................. Chejupontius Lee J & Kim IH, 2023 View in CoL

22. Exopod of antenna 1-segmented, bearing 3 setae ......................... ...................................................... Glyptotrogus McKinnon, 1988 View in CoL

- Exopod of antenna represented by single seta on small papilla .... ................................................................................................... 23

23. Leg 1 with 2 inner setae on second endopodal segment and typically with 3 outer spines on third exopodal segment .............. ................................................................. Artotrogus Boeck, 1860 View in CoL

- Leg 1 with 1 inner seta on second endopodal segment and typically with 2 outer spines on third exopodal segment .............. ................................................................ Tardotrogus Eiselt, 1961 View in CoL