A new species of Careproctus (Cottoidei: Liparidae) from the Falkland Plateau, southwestern Atlantic, with COI-based phylogenetic analysis Villarroel-Perez, Martin L. Chernova, Natalia V. Weston, Johanna J. N. Vukasin, Vedrana Shcherbich, Zhanna Zootaxa 2026 2026-03-19 5777 3 453 470 Villarroel-Perez & Chernova & Weston & Vukasin & Shcherbich 2026 [151,478,223,249] Liparidae Careproctus Animalia Scorpaeniformes 3 456 Chordata species argosgeorgiae sp. nov.  ( Figures 1–5; Table 1)     Holotype.MNHN- ICT 7645, female 294 mmTL, 255 mmSL. Falkland Plateaunortheast of Falkland Islands, 50°32’ S, 53°54’ W, depth  1680 m,  10.10.2024(UTC-3), F/ VCFL Hunter, longline (umbrella), line 3476/station 1815, FIFDgrid XL-AW; collector Martin L. Villarroel-Perez.   Diagnosis.  Careproctus argosgeorgiae  sp. nov.is distinguished from congeners by the following combination of characters: vertebrae 47; dorsal-fin rays 42; anal-fin rays 34; pectoral-fin rays 37; pleural ribs in three pairs, two of which are strongly developed; teeth simple; gill slit long, about half HL and reaching pectoral-fin ray 18; pelvic disk large, about 33% HL; distance from disk to anus greater than or equal to disk length; pectoral-fin upper lobe 67% HL; skin naked, with thick subcutaneous gelatinous tissue; color uniformly light orange, with deep orange margins of disk and pectoral fins.   Description.Dorsal-fin rays 42, first ray between neural spines 2 and 3. Anal-fin rays 34, with three anterior rays before the first haemal spine. Caudal-fin principal rays 12 (6 upper and 6 lower); procurrent rays 3 (2 upper and 1 lower) ( Fig. 3); caudal-fin formula 15 (2+6/6+1). Hypural plate structure indistinguishable on radiographs. Vertebrae 47 (pre-caudal 12 + caudal 35, including urostylar center). Pleural ribs in three pairs: two strong pairs on vertebrae 10 and 11 ( Fig. 2D); and a third pair thin and short (hardly visible) on vertebra 12. Counts and measurements are provided in Table 1. Body stout and not humpback ( Fig. 1). Head large, 3.5 inSL; pre-caudal part of body almost half of SL (48%). Maximal body depth equal to head length (99% HL), depth at A-fin origin almost equal to head depth (16 and 19% SL), depth at caudal peduncle 2% SL (8% HL). Head not deep at occiput, depth (66% HL) somewhat less than width (74% HL). Snout, 42% HL in length, not protruding above upper jaw. Nostrils one pair; tube width 2.1% HL. Mouth horizontal, terminal; width between corners of mouth about half of head length (54% HL). Teeth simple, conical, and sharp ( Fig. 2C), in numerous oblique rows, 6–7 teeth in a row near jaw symphysis. Eye small; diameter 4.6% SL ( 6.2 inHL); pupil round. Interorbital width 11.2% SL (2.4 times eye diameter). Postorbital length 14% SL (3.0 times eye diameter). Gill slit long, 13% SL (2.8 times eye diameter), almost equal to half the head length (45% HL) and reaching pectoral-fin ray 18, ventral end about level with mouth cleft. Opercular flap prominent, tip rounded when fresh and angled after fixation ( Fig. 1C). Pore formula 2–6–7–1 ( Fig. 2A). Chin pores closely spaced (~2 pore diameters), preoperculomandibular pores 2–4 separated by ~4 pore diameters. Dorsal fin not deep, with 3 or 4 anterior rays obviously erectile, tips standing out from fin membrane ( Fig. 1A). Caudal fin length 27% SL. Dorsal and anal fins overlap caudal fin by about three quarters of its length. Pectoral fin distinctly notched, with 37 rays: 29 inupper lobe, including shortest in notch, and 8 inlower lobe. Pectoral fin upper lobe rather long (67% HL), reaching anal-fin origin; lower-lobe rays no longer than upper-lobe rays, almost reaching anus. Pectoral girdle broken, lower part missing ( Fig. 4); scapula and two upper radials present; scapula and radials notched, with fenestrae in the cartilaginous plate between adjacent elements. Pelvic disk longitudinally oval (length 1.2 times width), located below gill slit. Disk length 32.6% HL ( 3.1 inHL), disk width 27.2% HL. Anterior fold of disk and segmental pads in central part not differentiated, central part of disk not depressed, diameter larger than width of marginal part ( Fig. 2B). Disk to anus distance about equal to disk length (10.0% and 9.2% SL). Anus opening well behind head (pre-anal length 128% HL), on vertical line near end of longest ray of the pectoral-fin. Distance from anus to anal-fin origin 1.8 times distance from posterior margin of disk to anus. Stomach and pyloric caeca not examined; otoliths not extracted. Gelatinous subcutaneous tissue (=subdermal extracellular matrix sensu Eastman et al.1994) quite thick when fresh; dorsal-fin rays covered by this tissue on proximal one-third of fin length; anal-fin rays completely embedded in tissue along anterior half of fin length. Skin naked, prickles absent. Female with large light-yellow eggs of approximately equal size, averaging 5 mmdiameter, largest 5.7 mm. Color when fresh uniform light orange with rose tint; margins of disk and ends of pectoral-fin rays orange. Oral cavity pale; gill cavity orange brown; gills reddish brown. Peritoneum brown with darker dispersed pigments. Coloration after fixation in formaldehyde and after preservation in alcohol pale ( Fig. 1C).   Etymology.The specific epithet argosgeorgiae honors the F/V Argos Georgia, a longliner that sank in the South Atlantic near the Falkland Islandson 22 July 2024, resulting in the loss of 13 lives and 14 survivors, including two fisheries observers. The response to the tragedy reflects the resilience and compassion of the South Atlantic islands community and underscores the human risks of deep-sea fishing in subantarctic and Antarctic waters. The epithet is a Latin feminine genitive meaning “of the Argos Georgia”, commemorating the vessel, its crew, and all those connected to it.   Distribution.Known from a single specimen captured on the Falkland Plateau, northeast of the Falkland Islands, at a bathydemersal depth of 1680 m.  Capture and associated fauna.The fish was incidentally recovered during hauling of umbrella-type longline gear targeting  Dissostichus eleginoides Smitt, 1898in waters northeast of the Falkland Islands, at depths of approximately 1040–1790 m. The individual was unhooked at the time of collection and exhibited a ruptured abdominal wall with extruded ripe eggs. The bycatch composition (%) was dominated by deep-sea fish species, including the elasmobranchs Antarctic starry skate  Amblyraja georgiana Norman, 1938and butterfly skate  Bathyraja papilionifera Stehmann, 1985( Rajiformes: Rajidae) (41%), the Southern sleeper shark  Somniosus antarcticus Whitley, 1939( Squaliformes: Somniosidae) (2%) and the osteichthyans, mainly big-eye grenadier  Macrourus holotrachys Günther, 1878( Gadiformes: Macrouridae) (35%) and blue antimora  Antimora rostrata Günther, 1878( Gadiformes: Moridae) (22%). Benthic invertebrates, including cold-water corals and sponges that are VME indicator taxa ( Huvenne et al. 2011; Robert et al. 2020), together with lithodid crabs, collectively accounted for only 0.02% of the total bycatch weight recorded across all hauls.   Biology. The holotypeis a ripe female (maturity stage V), weighing 392 g(wet weight at sea), with large eggs; the specimen was collected in October( Southern Hemisphere). Anelongate, worm-like ectoparasite was attached to the caudal region on the left side of the body.  Comparisons.Of the eighteen species of  Careproctusknown from southern South America and adjacent waters,  C. atakamensisAndriashev, 1998,  C. aureomarginatus,  C. macranchusAndriashev, 1991, and  C. magellanicus Matallanas & Pequeño, 2000have more vertebrae (51–59) than  C. argosgeorgiae  sp. nov.(47). In contrast,  C. falklandicus,  C. fueguensis Matallanas & Piacentino, 2019,  C. pallidus Vaillant, 1888, and  C. patagonicus Matallanas & Pequeño, 2000have fewer vertebrae (36–40). Unlike  C. argosgeorgiae  sp. nov., most of the other listed species lack pleural ribs, including  C. acaecusAndriashev, 1991,  C. aculeolatus,  C. armatus,  C. cactiformis Andriashev, 1990,  C. minimusand  C. stigmatogenus. By the presence of two pairs of strong pleural ribs,  C. argosgeorgiae  sp. nov.is similar only to  C. atrans,  C. herwigiAndriashev, 1991, and  C. smirnovi. It differs from  C. atransin having a higher number of pectoral-fin rays (37 vs. 26). Of the remaining two species,  C. argosgeorgiae  sp. nov.differs from  C. herwigi, described from northern Argentina( 41°13’ S, 1250 m), by the presence of simple teeth (vs. three-tuberculated teeth), a higher number of vertebrae (47 vs. 45), a longer gill slit reaching the 18th pectoral-fin ray (vs. 7–8 rays), and a gill slit approximately half of head length (vs. one-third). Additional differences include a smaller eye ( 6.2 inHL vs. 4.4), and a distance from disk to anus approximately equal to disk length (vs. about half of disk length). The new species is most similar to  C. smirnovi, which is known from waters north of the Falkland Islandsat depths of 1500–1580 mbased on two specimensof 204 and 186 mmSL ( Andriashev 1991 a, 2003; this paper: Fig. 5).  Careproctus argosgeorgiae  sp. nov.is larger in size and agrees with  C. smirnoviin the presence of pleural ribs, simple teeth, a similar number of vertebrae, dorsal-, pectoral- and caudal-fin rays, a similar gill slit size ( Table 1), and in the peritoneum coloration. However, it differs in having a less humpbacked occiput, an opercular flap positioned below the level of the eye, the upper pectoral-fin ray at mouth-cleft level, and a thicker, well-developed subcutaneous layer covering the origins of the dorsal and anal fins.   FIGURE 3.  Careproctus argosgeorgiae  sp. nov., holotype. Caudal-fin secondary rays (shown by arrows): two upper and one lower. Scale indicated by grid squares (1 cm).   FIGURE 4.Right pectoral girdle and fin of  Careproctus argosgeorgiae  sp. nov., holotype. Abbreviations: C—cleithrum; Lb—basal cartilaginous plate; sc—scapula; R—two radials; F—two fenestrae;?—indicating missing parts damaged during processing. Scale indicated by grid squares (1 cm). Additional differences between  C. argosgeorgiae  sp. nov.and  C. smirnoviinclude fewer anal-fin rays (34 vs. 36–37), a greater maximal body depth (28.0 vs. 25.8–26.2% SL), a shorter pre-dorsal length (32.3 vs. 34.4–35.0% SL), greater distances from chin to disk (15.3 vs. 13.3–14.0% SL) and from chin to anus (32.1 vs. 26.5–30.1% SL), and a longer upper lobe of the pectoral-fin (67 vs. 58–60% HL). The anus is positioned more posteriorly, with the distance from disk to anus larger (10.0 vs. 3.5–7.5% SL) and exceeding disk length (vs. less than disk diameter). In addition, the central part of the disk by diameter is larger than the width of its marginal part (vs. smaller than the marginal part), and the interorbital width is greater (39.7 vs. 34.2–35.8% HL). Color differences are also distinct with the body uniformly light orange and the disk and pectoral fins having deep orange margins (vs. rose-lilac coloration, darker posteriorly). Some of the observed differences between  C. argosgeorgiae  sp. nov.and  C. smirnovimay be influenced by specimen condition at fixation, particularly pre-dorsal-fin length and chin-to-disk distance. Nevertheless, most characters are interpreted as interspecific differences, supporting the recognition of  C. argosgeorgiae  sp. nov.as a distinct species.   FIGURE 5.Map of Falkland Islands showing capture localities of  Careproctus argosgeorgiae  sp. nov.(holotype),  C. smirnovi(holotype left and paratype right), and other  Careproctusspecies reported from the area: 1,2—  C. maculosusand  C. stigmatogenus; 3—  C. minimus; 4—  C. falklandicus; 5—  C. armatus; 6—  C. aureomarginatus; 7—  C. atrans; and 8—  C. aculeolatus. Species coordinates taken from original descriptions. Falkland Islands inner (FICZ) and outer (FOCZ) conservation zones also shown. A comparison is also provided with  C. solovjevae Balushkin, 2012, originally described in the genus  Volodichthys Balushkin, 2012, because it was considered by its author to be closest to  C. smirnovi( Balushkin 2012), to which the new species is also most similar. Available data ( Table 1) indicate that  Careproctus argosgeorgiae  sp. nov.resembles  C. solovjevaein vertebral number and the presence of pleural ribs, but differs in having a gill slit reaching anterior to the 18th pectoral-fin ray (vs. 10–13), a smaller eye (16.2 vs. 20.6–25.2% HL), a smaller disk (32.6 vs. 37.2–42.4% HL), a shorter distance from anus to anal-fin origin (17.9 vs. 20.2–20.4% SL), and distinct coloration (body light orange vs. gray-lilac, darker posteriorly; peritoneum brown vs. brown with a greenish tint). Except as noted above, six other species of  Careproctuspossessing two or three pairs of long pleural ribs are known from the Southern Hemisphere, all of which differ from  C. argosgeorgiae  sp. nov.Three species have higher vertebral counts:  C. albescens Barnard, 1927from South Africa(60–63),  C. novaezelandiae Andriashev, 1990from bathyal depths of the New ZealandPlateau (53–54), and  C. paxtoni Stein, Chernova & Andriashev, 2001from waters off New South Wales (58–59). Two species have similar vertebral (46–47) but differ in tooth morphology (three-lobed or with shoulders) and in having a shorter gill slit reaching only to the 5th–6th pectoral-fin rays in  C. catherinaefrom the Ross Sea, or to the 7–11th rays in  C. parinifrom the South Shetland Islands ( Andriashev 2003).   TABLE 1.Counts and measurements of  C. argosgeorgiae  sp. nov.and the type specimens of  C. smirnoviand C.   solovjevae; diagnostic characters of the new species are marked in bold. F=female; M=male.     Characters   C. argosgeorgiae  sp. nov.   C. smirnovi   C. solovjevae  Holotype Holotype Paratype Holotype Paratype  Museum number MNHN- ICT 7645 ZIN 49589 MGU 13688 ZIN 55054 ZPM PGU 393  SL, sex 254.8, F 204, M 186, F 332 F 343 F  Vertebrae 47 (12+35) 48 (11+37) 48 (11+37) 48 (13+35) 49 (12+37)  Pleural ribs, pairs 3 3 – 3 –  Dorsal-fin rays 42 43 43 43 44  Anal-fin rays  34 37 36 36 37  Pectoral-fin rays 37 (29+8) 37 (29+8) 37 (29+8) 35–37 (6–8+28– 29) 35, 36  Caudal-fin rays 15 (2+6/6+1) 14 (2+5/6+1) 13(14?) 14 (2+5/6+1) 14  Gill slit reaching to in front of pectoral-fin ray  18 14 17 13 10  Pores 2–6–7–1 2–6–7–1 – 2–6–7–1 –   As % SL:  Head length 28.3 29.4 30.1 30.7 28.9  Head width 20.9 22.1 20.5 22.9 23.3  Body depth  28.0 26.2 25.8 20.5 21.3  Depth at A-fin origin  15.9 20.6 ca. 18 23.5 26.2  Pre-dorsal length  32.3 34.4 35.0 – –  Pre-caudal length 47.9 44.0 52.6 – –  Chin to disk  15.3 13.3 14.0 14.2 11.5  Chin to anus 32.1 26.5 30.1 34.0 32.6  Disk 9.2 10.3 9.1 8.7 / 11.4 1 12.2  Disk to anus  10.0 3.5 7.5 9.3 9.8  Anus to anal-fin origin 17.9 12.8 18.8 20.2 20.4  Pectoral-fin upper lobe  19.0 17.2 18.3 14.7 15.4  Pectoral-fin lower lobe  16.1 15.7 15.6 14.2 13.4  Snout 11.8 11.8 12.9 13.2 15.2  Gill slit, length 12.8 13.8 15.1 13.8 12.8   As % HL  Head width 73.8 75.0 Ca.78 – –  Eye  16.2 20.0 16.2 20.6 25.2  Interorbital 39.7 34.2 35.8 39.2 44.0  Gill slit, length 45.1 46.7 50.0 45.1 44.4  Disk 32.6 35.0 30.2 37.2 42.4  Pectoral upper lobe  67 58.4 60.4  –  –  Color of body  Light orange Rose-lilac, darker posteriorly Darker than the holotype Grey-lilac, darker posteriorly Grey-lilac, darker posteriorly  Peritoneum Brown Light brown Light brown Brown with greenish tint Brown with greenish tint  Data from This study Andriashev (1991, 2003)  Balushkin (2012)   1 Balushkin (2012)gives different data for length of the disk of the holotype of  V. solovjevaein his diagnosis and Table 2.   TABLE 2.GenBank accession numbers and references for all samples included in the analysis of the COI barcoding gene. Some identifications present in GenBank are outdated or incorrect; those updated in this study and in Orr et al. (2019, 2020), are shown, with the original GenBank identifications in parentheses. Asterisks denote unpublished data.     Species  GenBank Accession Number  References  Family: Cyclopteridae    Aptocyclus ventricosus AP004443  Miya et al. (2003)  Family: Liparidae    Careproctus acanthodes LC380018 Kai*    Careproctus ambustus MN126594  Orr et al. (2020); as  C. cf. melanurus Orr et al. (2019)     Careproctus argosgeorgiae sp. nov.  PV962829  Present Study    Careproctus georgianus EU326327  Rock et al. (2008)    Careproctus longifilis( attenuates) FJ164428  Steinke et al. (2009)    Careproctus barbatulus LC773198  Kai et al. (2024)    Careproctus sp. nov.( canus) FJ164432  Steinke et al. (2009); Orr (in preparation)    Careproctus colletti LC337287 Kai*    Careproctus continentalis HQ712898  Dettai et al. (2011)    Careproctus cyclocephalus LC337280 Kai*    Careproctus cypselurus KY570326 Elz et al.*    Careproctus furcellus LC437091  Matsuzaki et al. (2020)    Careproctus gilberti MH715569  Orr et al. (2019)    Careproctus iacchus LC349296  Kai et al. (2018)    Careproctusio LC789195  Kai et al. (2024)    Careproctus longibarbatus LC773195  Kai et al. (2024)    Careproctus longidigitus LC495314  Kai & Matsuzaki (2020)    Careproctus longipectoralis HQ712900  Dettai et al. (2011)    Careproctus macrodiscus LC380009 Kai*    Careproctus marginatus LC379996 Kai*    Careproctus melanurus MH715572  Orr et al. (2019)    Careproctuscf. melanurus MH715571  Orr et al. (2019)    Careproctus mederi LC773185  Kai et al. (2024)    Careproctus notosaikaiensis LC380012 Kai*    Careproctus ostentum MH715573  Orr et al. (2019)    Careproctus ovigerus(  georgianus) FJ164449  Steinke et al. (2009)    Careproctus ovigerus(  georgianus) FJ164448  Steinke et al. (2009)    Careproctus pellucidus LC380014 Kai*    Careproctus rastrinus JF952697  Zhang & Hanner (2011)    Careproctus rausuensis LC412486  Matsuzaki et al. (2020)    Careproctus reinhardti HQ712338  Mecklenburg et al. (2011)    Careproctus rhomboides LC773204  Mori et al. (2025)    Careproctus roseofuscus LC380011 Kai*    Careproctus scottae MH715574  Orr et al. (2019)    Careproctus shigemii LC513147  Matsuzaki et al. (2020)    Careproctus simus LC380005 Kai*; used in Orr et al. (2019)    Careproctus spinulosus LC773203  Kai et al. (2024)  ......continued on the next page 2024-10-10 V, FIFD Hunter & Martin L. Villarroel-Perez. Falkland Islands 1680 -50.533333 Falkland Plateau 1096 -53.9 3 456 1 holotype V An October Southern Hemisphere 6 459 1 holotype