A new genus and species ofApseudidae, and a new species of Bunakenia (Crustacea Tanaidacea: Apseudomorpha) from the Northwest Atlantic and Gulf of Mexico Author Drumm, David T. Author Heard, Richard W. text Zootaxa 2022 2022-08-15 5175 1 31 54 journal article 123827 10.11646/zootaxa.5175.1.2 6d0ace79-5634-407b-a8d6-7a3107577faa 1175-5326 7003181 21211984-D237-4579-AAA0-8268D6BFB104 Pseudobunakenia anablesis n. sp. ( Figs 1–9 ) ? Apseudes sp. A sensu McSweeny, 1968 (figs 8–13); Heard et al. , 2004 (figs 28, 35). ? Apseudes spinosus sensu Dawson, 1966 ( non M. Sars, 1858). Diagnosis. As for the genus (currently monotypic). Material examined. Holotype : female ( ♀ ), 6.5 mm , ( USNM 1666244 ), station 4 . Allotype : male ( ♂ ), 5.0 mm, ( USNM 1666245 ) . Paratypes : 1 ♀ ( 6.5 mm ), 1 ♂ (4.0 mm) ( USNM 1666246 ), station 2 ; 1 ♂ (4.0 mm) ( USNM 1666247 ), station 1 ; 1 ♂ (5.0 mm) ( USNM 1666248 ), station 18 ; 2 ♂♂ ( 4.5 mm ) ( USNM 1666249 ), station 10 ; 1 ♂ ( 5.5 mm ) ( USNM 1666250 ), station 9 ; 1 ♀ (damaged), 1 ♂ ( 3.5 mm ) ( USNM 1666251 ), station 7 . Etymology . From anablesis- Greek for ‘postponement,’ ‘delay;’ alluding to the fact that it has taken over 50 years to formally describe this species since it was first discovered by Dawson (1966) and McSweeny (1968) . Description . Adult female. Holotype : ( Fig 1A ). Paratypes : ( Figs 1B – 7E ). Body ( Figs 1A–B ; 2– 3 ) about 6.2 times as long as wide. Cephalothorax as long as wide, about 15% of body length, about as long as first two pereonites combined, naked; rostrum broad at base with rounded shoulders, anterior portion produced in acute tip; eyelobes present, terminating distally in curved spine on ventro-lateral margin; epistome present. Pereon about 60% of body length; pereonite 1 shortest, more than twice as wide as long; pereonites 3 and 4 longest and subequal; pereonites 1 and 2 have rounded lateral margins while succeeding pereonites have nearly straight margins; pereonites 3 and 4 length subequal to width, all other pereonites wider than long, with setae on antero- and postero-lateral corners; pereonites 3–6 ( Figs 1B , 2 ) with ventrally directed spine on anterolateral margins; pereonites 2–4 with smaller inconspicuous, ventrally directed spine on posterolateral corners (this character is difficult to observe in smaller specimens and seems to be damaged in some other specimens); hyposphenia on pereonites 2, 3, and 6 ( Fig 3 ). Pleon as long as first two pereonites combined, about 16% of body length; pleonites expanded laterally into spiniform projection with plumose setose margins; hyposphenia present on pleonite 1. Pleotelson slightly longer than wide, about 6% of body length, about twice as long as one pleonite, with few setae on lateral and dorsal margins, and slight lateral projection anteriorly. Antennule ( Fig 1C ) peduncle article 1 about half as long as carapace, 3.2 times as long as wide, with six simple setae on inner margin and four simple setae and six PSS on outer margin; article 2 less than half length of article 1 with seven simple setae and three PSS; article 3 nearly half as long as article 2 with three distal simple setae and one distal PSS; article 4 (common article) about half as long as article 3 with two PSS on dorsal surface. Accessory flagellum with three articles, each one with at least one simple seta and one PSS. Main flagellum with seven articles with one aesthetasc on articles 3 and 5. Antenna ( Fig 1D ) peduncle with five articles; article 1 with inner distal projection, naked; article 2 as long as succeeding two articles combined, with one short simple seta on inner and outer margins; squama extending to midlength of article 5, bearing six simple setae; article 3 short, with two long inner simple setae; article 4 about twice as long as article 3, with two PSS on ventral surface; article 5 as long as article 2, with four PSS and two simple setae. Flagellum with five articles. Labrum ( Fig 4A ) with medial depression bearing hair-like setae on either side. FIGURE 1. Pseudobunakenia anablesis , n. gen., n. sp. , adult female. A, habitus (dorsal view); B, pereon (lateral view); C, antennule (dorsal view); D, antenna (ventral view). Scale bars: A = 1.0 mm; C = 0.2 mm; D = 0.1 mm. FIGURE 2. Pseudobunakenia anablesis , n. gen., n. sp. , adult female. Pereon showing anterolateral apophyses of pereonites 3–6 (oblique view). Photo by D. Drumm. FIGURE 3. Pseudobunakenia anablesis , n. gen., n. sp. , adult female. Lateral view of pereon showing hyposphenia on pereonites 2, 3, and 6. Photo by D. Drumm. Mandibles ( Fig 4B–D ). Incisor process of right and left mandible with four teeth; lacinia mobilis of left mandible with six teeth; molar process with grinding surface having well-developed micro-denticles; palp article 1 with six long simple setae, about same length as article three, article 2 longest, articles 2 and 3 with long simple and short pectinate setae. Labium ( Fig 4E ) with outer margin spinulate, distal margin setulose; palp with lateral hair-like setae and three distal spiniform setae. Maxillule ( Fig 4F–G ) inner endite with five setulate setae, outer margin with hair-like setae ( Fig 4F ); outer endite with 11 spiniform setae ( Fig 4G ) and two subdistal bipectinate setae ( Fig 4F ), both margins with hair-like setae; palp biarticulate with four distally setulate setae increasing in length distally. Maxilla ( Fig 4H ) inner lobe of fixed endite with posterior row of four bipectinate setae increasing in length laterally and with long anterior row of setae; outer lobe of fixed endite with three trifurcate and one multifurcate spiniform setae, one setulate spiniform seta, several simple setae, posterior face with one setulate spiniform seta; inner lobe of moveable endite with two long simple setae; outer lobe of moveable endite with one denticulate and one plumo-denticulate setae; outer distal margin serrate. Maxilliped ( Fig 5A, B ) basis slightly longer than broad, naked (notwithstanding setules on outer proximal margin), outer distal corner produced ( Fig 5A ); endite ( Fig 5B ) with inner margin having four coupling hooks, row of seven setulate setae and several distal simple and blunt-tipped setae, caudo-distal spiniform seta distally setulate, outer margin with short hair-like setae; palp article 1 with outer distal corner produced and bearing one spiniform seta; article 2 with long and shorter simple setae on inner and distal margins; article 3 broader than long with several simple setae on inner mid-distal margin; article 4 short with five distal simple setae. FIGURE 4. Pseudobunakenia anablesis , n. gen., n. sp. , adult female. A, labrum; B, right mandible; C, left mandible; D, right molar process; E, labium; F, maxillule; G, maxillule (outer endite); H, maxilla. Scale bars: A, E, H = 0.05 mm; B, F = 0.1 mm. FIGURE 5. Pseudobunakenia anablesis , n. gen., n. sp. , adult female. A, maxilliped; B, maxilliped endite; C; epignath; D, cheliped (outer view); E, pereopod 1 (outer view); F, pereopod 1 merus and carpus (inner view); G, pereopod 1 exopod. Scale bars: A, C = 0.1 mm; D, E = 0.2 mm. Epignath ( Fig 5C ) with stout, setulate spiniform seta; anterior margin with bilobed flap. Cheliped ( Fig 5D ) basis triangular, about 1.6 as long as broad, middle of ventral margin produced with a short and stout spiniform seta, and several simple setae on outer and inner faces and ventral margin; merus about 2.5 times as long as broad with several simple setae; carpus elongate, narrow, about 4 times as long as broad with ventral, dorsal, and dorsodistal simple setae; propodus with several simple setae on outer face of palm and dorsally, fixed finger with three ventral simple setae, cutting edge with row of spinules and row of short simple setae on outer face; dactylus with four spinules on distal half of cutting edge and three simple setae on inner face, unguis about one third length of dactylus; exopodite, last article with four plumose setae. Pereopod 1 ( Fig 5E–G ) coxa setose with forward-directing spine; basis almost twice as long as broad, with several simple setae ventrodistally and on dorsal margin, ventrodistal spiniform seta; ischium wider than long with two ventrodistal simple setae; merus widest distally, about 2.6 times as long as broad, with several simple setae on ventral margin and inner and outer surfaces and a spiniform seta on ventrodistal corner; carpus wider than long, with simple setae on ventral and dorsal margins and inner and outer surfaces, two ventral spiniform setae and one dorsodistal spiniform seta about half length of propodus; propodus slightly shorter than carpus, with simple setae on ventral, dorsal, and distal margins, five ventral spiniform setae and two dorsodistal spiniform setae; dactylus length slightly shorter than propodus with one mid-ventral spinule and one minute seta proximal to junction with unguis, two dorsal setae, unguis simple, about one third total length of dactylus; exopod last article with six plumose setae. Pereopod 2 ( Fig 6A ) basis about three times as long as wide with two setae on dorsal margin and several ventral and ventrodistal simple setae; ischium about as wide as long, with two ventrodistal simple setae; merus about twice as long as wide with several simple setae on ventral and dorsal margins and outer surface; carpus almost twice as long as wide with several simple setae on ventral and dorsal margins; propodus shorter than carpus, about twice as long as wide with several ventral, dorsal, and distal simple setae, one dorsal PSS; dactylus with one minute distal seta on dorsal margin, dactylus + unguis slightly shorter than propodus. Pereopod 3 ( Fig 6B ) similar to pereopod 2, merus and carpus lacking dorsal setae. Pereopod 4 ( Fig 6C, D ) basis 2.8 times as long as wide with one small simple seta on inner and outer surfaces, one ventral and three dorsal PSS; ischium with one long and one short simple seta on ventrodistal corner; merus about twice as long as wide with four simple setae on ventral margin; carpus about 2.7 times as long as wide with five spiniform setae on outer margin and several simple setae on ventral margin and inner and outer surfaces; propodus almost half as long as carpus with several distal simple setae and four long dorsodistal pectinate spiniform setae, dorsodistally with row of about seven short bipectinate spiniform setae, one proximal PSS on dorsal margin; dactylus with one minute seta distally on ventral margin; unguis + dactylus slightly more than half length of propodus. Pereopod 5 ( Fig 7A, B ) similar to pereopod 4; basis three times as long as wide with one simple seta on ventrodistal corner, one ventral and two dorsal PSS; ischium with three simple setae on ventrodistal corner; carpus without spiniform setae; propodus similar to pereopod 4 but with fewer (about four) dorsodistal short bipectinate spiniform setae; dactylus with one seta on mid outer surface; unguis + dactylus length subequal to propodus. Pereopod 6 ( Fig 7C ) basis about 2.8 times as long as wide with two simple setae on ventrodistal corner; ischium with three simple ventrodistal setae; merus about 1.8 times as long as wide with three plumose setae on dorsal margin, two simple setae and one spiniform seta (broken off) on ventral margin, and one simple seta on outer surface; carpus about 1.9 times as long as wide with three plumose setae on dorsal margin, two simple and two spiniform setae on ventral margin, and three simple setae on outer surface; propodus subequal to carpus length with several simple setae on outer surface and ventral and distal margins, inner surface with row of about 17 bipectinate spiniform setae, and one PSS midway on dorsal margin; dactylus with minute seta near dorsal margin and distally on ventral margin; unguis + dactylus length shorter than propodus. Pleopod ( Fig 7D ) foliaceous, basal article slightly longer than wide with five plumose setae on lateral margins; exopod shorter than endopod, with 21 plumose setae; endopod with 22 plumose setae. Uropod ( Fig 7E ) length less than half body length; basal article almost twice as long as wide with several distal simple setae; number of articles in exopod and endopod hard to discern due to multiple pseudo-articulations. Male ( Figs 8–9 ) similar to female but with the following differences: Pereon with hyposphenia behind maxilliped insertion and on pereonites 2 and 3 and genital cone on pereonite 6. FIGURE 6. Pseudobunakenia anablesis , n. gen., n. sp. , adult female. A, pereopod 2 (outer view); B, pereopod 3 (outer view); C, pereopod 4 (inner view); D, pereopod 4 carpus, propodus, and dactylus (outer view). Scale bars = 0.2 mm. FIGURE 7. Pseudobunakenia anablesis , n. gen., n. sp. , adult female. A, pereopod 5 (outer view); B, pereopod 5 propodus and dactylus (inner view); C, pereopod 6 (outer view); D, pereopod 6 basis (outer view showing plumose setae on dorsal margin of a specimen from South Carolina); E, pleopod; F, uropod. Scale bars = 0.2 mm. FIGURE 8. Pseudobunakenia anablesis , n. gen., n. sp. , adult male paratype. Photo by D. Drumm. Antennule ( Fig 9A ) more robust, peduncle article 1 2.7 times as long as wide. Main flagellum with eight articles with one aesthetasc on articles 2, 3, 4, and 6. Cheliped ( Fig 9B, C ) more robust, carpus about 2.6 times as long as wide; chela with wide gap between fingers. Intraspecific variation. One preparatory female has six ventral spiniform setae on the propodus of pereopod 1. The allotype male has four plumose setae on the dorsal margin of the carpus of pereopod 6 and one and three spiniform setae on the ventral margin of the merus and carpus, respectively. One male has two plumose setae proximally on the dorsal margin of the pereopod 6 basis. Plumose setae were not observed in other specimens, so it is not clear if these setae are easily broken off or if it was an anomaly, although specimens from South Carolina have several plumose setae on the dorsal margin of the pereopod 6 basis ( Fig 7D ). Some adult females from Tampa Bay and South Carolina had five plumose setae on the dorsal margin of the carpus of pereopod 6. Type locality. Gulf of Mexico , Southwest coast of Mexico off the coast of Campeche , 19°8’24’’N , 91°54’0’’W , depth 22 m in soft bottom substrata . Distribution. Southern Gulf of Mexico [Campeche region ( type locality)], Texas (senior author, pers. observ.), Louisiana to Florida Keys; U.S. East Coast: Florida (Biscayne Bay) northward to South Carolina (off Port Royal Sound). Remarks. McSweeny (1968) described a new apseudid species from South Florida ( Apseudes sp. A ) in his unpublished graduate thesis that is very similar and possibly conspecific with the new species described here. The only major differences based on comparison with his description and illustrations are that Apseudes sp. A : 1) has the inner flagellum of the antennule 4 articulate, and 2) the merus and carpus of pereopod 6 lack plumose setae. It is possible that his specimens either had these setae broken off or that he just did not observe the setules, so the status is uncertain until topotypical material can be examined. Specimens examined from the western coast of Florida and from South Carolina labeled as Apseudes sp. A are seemingly conspecific with the new species (senior author, pers. observ.). FIGURE 9. Pseudobunakenia anablesis , n. gen., n. sp. , adult male. A, antennule (ventral view); B, cheliped (outer view); C, male chela showing gape when fixed finger and dactylus are pressed together. Scale bars = 0.2 mm. Photo by D. Drumm. Pseudobunakenia anablesis n. gen., n. sp. can be distinguished from the apseudids presently known from the GOM/NW Atlantic by the following combination of characteristics: 1) the anterolateral apophyses on pereonites not large and hook-like [as in Apseudopsis olimpiae ( Guţu, 1986 ) ], and 2) the presence of gaping chelae (present also only in the new Bunakenia species described below, but which lacks anterolateral apophyses on the pereonites). Pseudobunakenia anablesis is similar to Apseudopsis caribbeanus Guţu, 2006 , described off Cuba , but can be distinguished by having acute anterolateral apophyses on pereonites 3–6 (small lobate processes on A. caribbeanus ), pereonites 3–5 length subequal to width (wider than long in A. caribbeanus ), hyposphenia on pereonites 2–3, and 6 (on pereonites 2–4, and 6 in A. caribbeanus ), long and short setae on mandibular palp article 2 (only short setae in A. caribbeanus ), gaping chelae (gaping chelae lacking in A. caribbeanus ), and pereopod 1 propodus with five or six ventral spiniform setae ( 4 in A. caribbeanus ).