Two axiidean ghost shrimps (Crustacea: Decapoda) from India, Guyanacaris keralam sp. nov. (Axiidae) and Paragourretia galathea (K. Sakai, 2017) (Ctenochelidae) Author Padate, Vinay P. 0000-0002-2244-8338 Centre for Marine Living Resources & Ecology, Ministry of Earth Sciences, Government of India, Atal Bhavan, LNG Terminus Road, Puthuvype, Kochi, 682508, India. & vinaypadate @ gmail. com; https: // orcid. org / 0000 - 0002 - 2244 - 8338 vinaypadate@gmail.com Author Cubelio, Sherine Sonia Centre for Marine Living Resources & Ecology, Ministry of Earth Sciences, Government of India, Atal Bhavan, LNG Terminus Road, Puthuvype, Kochi, 682508, India. Author Takeda, Masatsune 0000-0002-0028-1397 Department of Zoology, National Museum of Nature and Science, Tokyo. 4 - 1 - 1 Amakubo, Tsukuba, Ibaraki, 305 - 0005, Japan. takeda @ kahaku. go. jp; https: // orcid. org / 0000 - 0002 - 0028 - 1397 takeda@kahaku.go.jp text Zootaxa 2022 2022-01-26 5093 2 195 217 journal article 2408 10.11646/zootaxa.5093.2.4 a29a1307-a6a4-4198-8653-e79c13f4d008 1175-5326 5905225 FA40C88B-9784-4DC0-9109-90936BAFE808 Guyanacaris keralam sp. nov. ( Figs 2–5 ) urn:lsid:zoobank.org:act: 6FE055EC-2D4E-46C7-80ED-4C30F540F940 Material examined . Holotype . Male ( CMLRE / IO /SS/AXI/00001, CL 50.0 mm, TL 119.0 mm), Arabian Sea , west off Kasaragod , Kerala , India , FORVSS station 31810, 12.10°N , 74.32°E , 316–326 m depth , 26 August 2013 , Expo model trawl, coll. Dr. Rajool Shanis C.P. Diagnosis. Rostrum with 4 or 5 lateral spines. Lateral gastric carina with 5 spines; submedian gastric carina with 6 spines; median gastric carina with 3 anterior spines, 1 tubercle and 4 posterior spines. Eyestalk short of midlength of rostrum. Antennular peduncle not reaching to distal margin of antennal article 4. Antennal article 4 longer than article 2, scaphocerite overreaching midlength of article 4. Chelipeds subequal, major P1 dactylus with 6 erect dorsal spines, minor P1 dactylus with 5 erect dorsal spines; fingers at least 3 times palm length. P3–4 propodi and dactyli with corneous movable spines. Description of holotype . Carapace minutely granular, sparsely setose ( Figs 1A, C , 2A, B ). Rostrum acute, 0.19 times post-rostral carapace length, 0.45 times length of front-to-cervical groove, acute, short of base of distalmost antennular article, and midlength of penultimate antennal article (article4), bearing 4lateral spines on the right margin, 5 lateral spines on the left margin anterior to supraocular spine, weakly continuous with lateral gastric carinae ( Figs 1A, C , 2A, B, D ). Supraocular spine slightly shorter than rostral spines, anterolateral margin with 1 antennal spine. Lateral gastric carina bearing 5 spines; submedian gastric carina bearing 6 spines; median gastric carina bearing 3 anterior spines, 1 tubercle and 4 posterior spines; cervical groove distinct, extending anteriorly up to hepatic region, unarmed; post-cervical and branchiostegal regions unarmed, low median longitudinal post-cervical carina present ( Figs 1A, C , 2A, B, D ). Thoracic sternite 7 (P4) deeply divided in midline over posterior two-thirds, bearing sharp oblique lateral ridge; sternite 8 (P5) with setose semicircular flap on anterior face at base of P5 ( Figs 1B , 2C ). Pleonal 1 pleuron twice as deep as middorsal length, bearing 1 ventral spine; pleuron 2 broad, lateral length 1.6 times dorsal length, gently convex anteroventrally, bearing 13 marginal spines ventrally; pleura 3–5 ventrally subquadrate, posterior margins almost straight, pleura 3–4 bearing 6 marginal spines each, pleuron 5 bearing 5 marginal spines; pleuron 6 bluntly triangular, bearing 1 ventral spine ( Figs 1A, C , 2A ); pleura 1–5 with lateral crease ( Figs 1C , 2A ). Ocular peduncle 0.46 times rostral length; cornea lightly pigmented ( Fig. 2B, D ). Antennular peduncle not reaching to distal margin of penultimate antennal article (article 4) ( Fig. 2B, D, E, F ). Antennal article 1 bearing 1 spine on distoventral margin, ventral margin with 1 row of blunt spinules; article 2 distal spine (stylocerite) slender, directed anteriorly, short of midlength of antennal article 4; scaphocerite gently curved, overreaching midlength of article 4, bearing mesial spine at base; article 3 with broad mesiodistal spine on ventral margin; article 4 length 1.40 times length of article 2 (excluding distal spine); article 5 0.46 times length of article 4 ( Fig. 2B, D, E, F ). Pleurobranch gills absent; well-developed epipods and podobranch gills on maxillipeds 2–3 and pereopods 1–4; 2 arthrobranch gills each on maxilliped 3 and pereopods 1–4. Maxilliped 3 coxa bearing 1 spine; basis bearing 1 spine; ischium ventral margin bearing 3 spines, crista dentata with 17–21 teeth ( Fig. 2G ); right merus ventral margin bearing 4 spines ( Fig. 3G ), left merus with 3 spines; right carpus ventral margin bearing 1 subdistal spine, left carpus spine damaged; exopod with well-developed flagellum, reaching distal end of merus ( Fig. 2H ). Chelipeds (PI) subequal in length, propodus of right P1 slightly more swollen, ornamentation slightly dissimilar. Major (right) P1 coxa bearing 1 curved spine proximally, 2 spines distally on ventral margin, lateral margin bearing 1 spine and 3 spinules; basis ventral surface bearing 1 spine, terminal spine on lateral margin behind ischial articulation; ischium ventral margin bearing 2 rows of 3–5 spines ( Fig. 3A, B ); merus dorsal margin bearing 5 spines, anterior 2 forming 1 pair with spinule at carpal articulation, outer ventral margin bearing 10 small spines and 8 spinules, inner ventral margin bearing 5 large spines, distoventral lobule with large hook-like spine, lateral surface sparsely spinose distally, mesial surface smooth ( Fig. 3A, B ); carpus dorsal surface bearing 3 spines, lateral surface bearing 12 spinules including 2 on distal margin, mesial surface bearing 1 pair of blunt spinules distally, ventral margin bearing 3 spinules distally ( Fig. 3A, B ); propodus dorsal margin bearing 2 irregular rows of 3–5 spines, ventral margin bearing 13 spines in lateral row, mesial surface inflated ( Fig. 1B ), bearing 13 spines (anterior largest), pollex (fixed finger) inner surface bearing 5 spines dorsally, lateral surface sparsely spinose, 2 irregular rows of 3 spines each proximally; pollex 3.00 times as long as upper palm, cutting edge straight with 30 bluntly triangular teeth ( Fig. 3A, B ); dactylus dorsal margin with 6 spines, lateral and mesial surfaces unarmed, cutting edge bearing 30 bluntly triangular teeth ( Fig. 4A, B ); both fingers heavily setose ( Fig. 1A, B, C ). Minor (left) P1 coxa bearing 1 curved spine proximally, 2 spines distally on ventral margin, lateral margin bearing 1 spine and 3 spinules; basis ventral surface bearing 1 spine, terminal spine on lateral margin behind ischial articulation; ischium ventral margin bearing 2 rows of 3–5 spines; merus dorsal margin bearing 5 spines, 1 spinule at carpal articulation, outer ventral margin bearing 9 small spines and 8 spinules, inner ventral margin bearing 4 large spines, distoventral lobule with large hook-like spine, lateral surface sparsely spinose distally, mesial surface smooth; carpus dorsal surface bearing 2 spines, lateral surface bearing 11 spinules including 2 on distal margin, mesial surface bearing 1 pair of blunt spinules distally, ventral margin bearing 2 spinules distally; propodus dorsal margin bearing 2 irregular rows of 3–4 spines, ventral margin bearing 14 spines in lateral row, mesial surface gently inflated ( Fig. 1B ), bearing 10 spines (anterior largest), pollex (fixed finger) inner surface bearing 3 spines dorsally, lateral surface sparsely spinose, 2 oblique rows of spines proximally, 2 spines in upper row, 5 spines in lower row; pollex 3.20 times as long as upper palm, cutting edge straight with approximately 29 bluntly triangular teeth ( Fig. 3C, D ); dactylus dorsal margin with 5 spines, lateral and mesial surfaces unarmed, cutting edge bearing 33 bluntly triangular teeth ( Fig. 4C, D ); both fingers heavily setose ( Fig. 1A, B, C ). FIGURE 2. Guyanacaris keralam sp. nov. , holotype, male, CL 50.6 mm, TL 119.0 mm (CMLRE/IO/SS/AXI/00001) from the Arabian Sea off Kerala, India. A, Carapace, pleon and tail fan, lateral view; B, Carapace, left eye, left antennule and left antenna, dorsal view; C, Thoracic sternites 7 and 8; D, Rostrum, left eye, left antennule and left antenna, dorsal view; E, Left antennule and left antenna, lateral view; F, Left antennule, left antenna and epistome, ventral view; G, Right maxilliped 3 (denuded), inner view; H, Left maxilliped 3, outer view. Scale bars: A–B = 10 mm; C–F = 2 mm; G–H = 5 mm. P2 ischium bearing 1 large subdistal and 4 proximal spinules ventrally; merus bearing 1 large subdistal and 2 smaller proximal spines ventrally; carpus 0.78 times as long as chela; propodus upper margin 0.77 length of dactylus ( Fig. 4A ), fingers bearing pectinate teeth on cutting margins ( Fig. 4A, B ). P3 ischium bearing 5 proximal spinules ventrally; merus bearing 1 distoventral spine; propodus 1.22 times as long as dactylus, lateral surface bearing transverse sets of corneous spines ( Fig. 4C ); dactylus curved, lateral surface bearing 2 rows of 5–10 corneous spines, distal tip corneous, tapering to a claw ( Fig. 4C, D ). P4 ischium bearing 5 proximal spinules ventrally; merus bearing 1 distoventral spine; propodus 3.04 times as long as dactylus, lateral surface bearing transverse sets of corneous spines ( Fig. 4E ); dactylus curved, lateral surface bearing 2 rows of 6–11 corneous movable spines, distal tip corneous, tapering to a claw ( Fig. 4E, F ). P5 propodus 2.55 times as long as dactylus, subchelate, with short fixed finger ( Fig. 4G ); dactylus unarmed, heavily setose proximally, distal tip corneous ( Fig. 4G, H ). Pleopod 1 present, bearing 2 long setae distally ( Fig. 4I ). Pleopod 2 endopod bearing appendix masculina and appendix interna attached at proximal one-thirds portion, appendix interna 0.33 times length of endopod, subequal to appendix masculina ( Fig. 4J ). Pleopods 3–5 appendix interna 0.36 times length of endopod. Telson 1.31 times as long as broad, lateral margin bearing 3 spines in the middle third portion, 1 spine in the posterior third portion, posterior margin broadly convex, densely setose with posteromedian spine, posterolateral angle unarmed; dorsal surface with 1 pair of submedian subcircular depressions anteriorly, 2 spines in each oblique row ( Fig. 4K ). Uropodal endopod 1.06 times as long as wide, with 3 lateral spines, longitudinal ridge bearing 5 spines. Uropodal exopod 1.34 times as long as wide, with 3 lateral spines, dorsal surface bearing 2 longitudinal ribs, inner rib unarmed, outer rib with 2 spines, posterolateral angle with 1 fixed spine; transverse suture with 9 spines ( Fig. 4K ). Preserved colouration (in formalin for 7 years and recently transferred to 70% ethanol) is brown with dark yellow setae; PI chelae and carpi light grey ( Fig. 1A, B, C ). Etymology. The species name is derived from the vernacular Malayalam word “Keralam” denoting the southwestern Indian state of Kerala ; used as noun in apposition. Remarks. Poore & Collins (2009) commented that Calocaris (Calastacus) hirsutimana Boesch & Smalley, 1972 , Axiopsis (Axiopsis) caespitosa Squires, 1979 referred to Acanthaxius by Sakai and de Saint Laurent (1989) , and Acanthaxius polychaetes Sakai, 1994 , differed from the typical Acanthaxius in the presence of male pleopod 1, absence of prominent supraocular spine, comparatively more compact propodus on the major cheliped with few lateral spines, and presence of prominent lateral spine on the telson; additionally, Acanthaxius spinulicauda ( Rathbun, 1902 ) reportedly differed from the type species A. pilocheira K. Sakai, 1987 in possessing a less spinose carapace. They further suggested the creation of new genera to accommodate these species. Sakai (2011) retained A. spinosissima in Acanthaxius due to the absence of male pleopod 1. He erected a new genus, Guyanacaris , for C. hirsutimana (as type species) and A. caespitosa , owing to an elongate, forwardly directed antennal scaphocerite and the presence of uniramous, bisegmented male pleopod 1. He erected another genus, Bruceaxius K. Sakai, 2011 , for A. polychaetes (as type species), owing to the presence of uniramous, bisegmented male pleopod 1, with a digitiform distal segment, carapace with anterolateral spine and postcervical carina, P1 chela with unarmed dorsal margin and thickly setose lateral surfaces, fingers of larger cheliped shorter than palm, those of smaller cheliped distinctly longer than palm, and pleonal 1–5 tergites and pleura separated by longitudinal carina. Moreover, he transferred A. spinulicauda to another genus Leonardsaxius K. Sakai, 2011 , owing to smooth submedian and lateral gastric carinae on the carapace. Dworschak (2013) and Dworschak and Poore (2018) recognized Guyanacaris for G. hirsutimana and G. caespitosa . Moreover, Dworschak and Poore (2018) considered Sakai’s (2011) definition of Guyanacaris to be weak. Sakai (2015) described a second species of Bruceaxius , B. thailandensis . Poore (2020) commented that A. polychaetes K. Sakai, 1994 and A. spinosissima ( Rathbun, 1906 ) probably belonged to Guyanacaris owing to the presence of multi-spinate lateral gastric carinae converging anteriorly on small supraocular spines, and a mesial spine at the base of scaphocerite. If A. polychaetes , type species of Bruceaxius , is considered to be a Guyanacaris , then Bruceaxius should be considered to be a synonym of Guyanacaris . With regards to B. thailandensis , it was noted that the line illustration of the antennal peduncle ( Sakai 2015 : Fig. 3A ) did not clearly indicate the presence of a mesial spine at the base of scaphocerite. In view of this, it is herein considered that B. thailandensis differs from the typical Guyanacaris in the absence of a mesial spine at the base of scaphocerite, major P1 carpus, propodus and dactylus with tuberculate upper margins, male pleopod 2 with tri-segmented appendix masculina ( Table 2 ). It is therefore suggested that this species may be tentatively retained in Bruceaxius . FIGURE 3. Guyanacaris keralam sp. nov. , holotype, male, CL 50.6 mm, TL 119.0 mm (CMLRE/IO/SS/AXI/00001) from the Arabian Sea off Kerala, India. A, Right pereopod 1, lateral view; B, Right pereopod 1, mesial view; C, Left pereopod 1, lateral view; D, Left pereopod 1, mesial view. Scale bars: A–D = 10 mm. FIGURE 4. Guyanacaris keralam sp. nov. , holotype, male, CL 50.6 mm, TL 119.0 mm (CMLRE/IO/SS/AXI/00001) from the Arabian Sea off Kerala, India. A, Right pereopod 2, lateral view; B, Right Pereopod 2 chela, lateral view; C, Right pereopod 3, lateral view; D, Right pereopod 3 dactylus, sub-dorsal view; E, Right pereopod 4, lateral view; F, Right pereopod 4 dactylus, lateral view; G, Right pereopod 5, lateral view; H, Right pereopod 5 dactylus, lateral view; I, male pleopods 1, posterior view; J, Left pleopod 2 exopod, endopod, appendix interna and appendix masculine, anterior view; K, pleomere 6, telson and right uropods, dorsal view. Scale bars: K = 10 mm; A–C, E, G = 5 mm; F, H–J = 2 mm; D = 1 mm. TABLE 2. Morphological comparison among the species of Guyanacaris K. Sakai, 2011 and Bruceaxius K. Sakai, 2011 .

Characters/Species	G. caespitosa ( Squires, 1979 )	G. hirsutimana ( Boesch & Smalley, 1972 )	G. keralam sp. nov.
Rostrum	overreaching base of penultimate anten- nular article	not reaching base of penultimate anten- nular article	not reaching base of distalmost antennular article
Rostral lateral armature	3 pairs of spines or 3–5 spinules	5 pairs of spines	4–5 spines
Carapace (excluding gastric carinae) orna- mentation	1 antennal spine	1 antennal spine	1 antennal spine
Carapace, lateral gastric carina	3–4 spines or 6–8 spines	6–7 spines	5 spines
Carapace, submedian gastric carina arma- ture	4–5 spines or 5–7 spines	5 spines	6 spines
Carapace, median gastric carinae armature	3 anterior spines followed by 1 tubercle, or 13 spines	8 spines	3 anterior spines followed by 1 tubercle and 4 posterior spines
Carapace, cervical groove armature	3 spines	smooth	smooth
Pleuron 1	acute	acute	acute
Pleura 1–5, marginal armature	with several spines	with several spines	with 1, 13, 6, 6, 5 and 1 spines, respec- tively
Ocular peduncle	overreaching distal tip of rostrum	overreaching distal tip of rostrum	not reaching midlength of rostrum
Antennular peduncle	reaching base of penultimate antennal article	not reaching midlength of penultimate antennal article	not reaching distal margin of penultimate antennal article
Antennal article 2, distal spine orientation	anterior	anterior	anterior
Scaphocerite	not reaching distal margin of penultimate antennal article	not reaching distal margin of penultimate antennal article	not reaching distal margin of penultimate antennal article
Scaphocerite, mesial spine at base	present	present	present
Maxilliped 3, ventral margin armature	not known	ischium with 2 spines, merus with 3 spines, carpus with 1 subdistal spine	ischium with 3 spines, merus with 3–4 spines, carpus with 1 subdistal spine
Relative size of chelipeds	unequal	unequal	Subequal
Length of pollex relative to upper palm	pollex of major P1 1.4 times upper palm length, that of minor P1 3.1 times upper palm length	pollex of major P1 1.5 times upper palm length, that of minor P1 1.66 times upper palm length	pollex of major P1 3.0 times upper palm length, that of minor P1 3.2 times upper palm length
P1 carpus, dorsal surface armature	5–8 spines or numerous denticles	2–3 spines	2–3 spines
P1 propodus, dorsal margin armature	2–3 pairs of spines or numerous denticles	2–3 spines	2 rows of 3–5 spines
P1 dactylus, dorsal margin armature	5 spines on minor P1	2 spines each on both P1	6 spines on major P1, 5 on minor P1

......continued on the next page TABLE 2. (Continued)

Characters/Species	G. caespitosa ( Squires, 1979 )	G. hirsutimana ( Boesch & Smalley, 1972 )	G. keralam sp. nov.
P2 merus, ventral margin armature	3 or 4 spines	4 spines	2 proximal and 1 distal spine
P2 carpus, ventral margin armature	absent	absent	absent
P3–4 propodus and dactylus armature	absent	absent	corneous movable spines on P3–4 propodi and dactyli
P5 propodus and dactylus armature	corneous denticles on P5 propodus only	absent	absent
Telson, lateral margin armature	2 spines	2 proximal and 1 distal spine	3 spines along middle third portion and 1 distal spine
Telson, posterolateral margin armature	absent	absent	absent
Uropodal endopod, lateral margin armature	2 spines	2 spines	3 spines
Uropodal exopod, lateral margin armature	5 spines (including 2 movable spines at edge of transverse suture)	2 spines	4 spines
Nature of appendix masculina on male pleopod 2	uni-segmented, distinctly shorter than ap- pendix interna	uni-segmented, distinctly shorter than ap- pendix interna	uni-segmented, subequal to appendix interna
Geographical distribution	Gulf of California, Pacific coasts of Costa Rica, Mexico, Nicaragua, Colombia and Peru ( Squires 1979 ; Hendrickx 1987 , 2004 ; Dworschak 2013 ; Dworschak & Poore 2018 )	Gulf of Mexico, tropical Atlantic off Guyana, Costa Rica, South Atlantic Bight off Georgia, South Carolina ( Boesch & Smalley, 1972 ; Heard et al . 2007 )	Southeastern Arabian Sea (present study)
Bathymetric range	72–200 m	62–232 m	326 m
References (for morphological charac- ters)	Squires (1979 : figs 2, 3), Sakai (2017a : figs 1A–B, 2A–B, 3C), Dworschak & Poore (2018 : fig. 1C)	Boesch & Smalley (1972 : figs 1–8)	Present study (Figs 1A–C, 2A–B, D–E, G–H, 3A–D, 4A, C–H, J–K)

......continued on the next page TABLE 2. (Continued)

Characters/Species	G. polychaetes (K. Sakai, 1994 )	G. spinosissima ( Rathbun, 1906 )	B. thailandensis K. Sakai, 2015
Rostrum	not reaching base of distalmost antennular article	reaching base of distalmost antennular article	not reaching base of penultimate antennular article
Rostral lateral armature	6–7 spines	3–4 pairs of spines	5–8 spines
Carapace (excluding gastric carinae) orna- mentation	1 antennal spine	3 hepatic spines, 2 anterolateral spines (including antennal spine)	1 antennal spine
Carapace, lateral gastric carina	5–6 spines	7 spines	7 spines
Carapace, submedian gastric carina armature	5–6 spines	8–9 spines	6–7 spines
Carapace, median gastric carinae armature	4 anterior spines followed by 1 tubercle and 6 posterior spines	5 anterior spines followed by 1 tuber- cle and 7 posterior spines	17 spines and 1 median tubercle
Carapace, cervical groove armature	smooth	11 spines	groove finely denticulate
Pleuron 1	acute	acute	less acute
Pleura 1–5, marginal armature	pleura 1, 3–6 with 1 spine each	pleuron 1 with several spines, pleura 2–3 with 2–3 spines	with 0, 9, 5, 4, 4 and 1 spines, respectively
Ocular peduncle	reaching midlength of rostrum	reaching distal tip of rostrum	not reaching distal tip of rostrum
Antennular peduncle	not reaching distal margin of penultimate antennal article	reaching distal margin of penultimate antennal article	reaching distal margin of penultimate antennal article
Antennal article 2, distal spine orientation	anterior	anterior	anterior
Scaphocerite	not reaching midlength of penultimate anten- nal article	not reaching distal margin of penulti- mate antennal article	not reaching distal margin of penultimate antennal article
Scaphocerite, mesial spine at base	present	present	?absent
Maxilliped 3, ventral margin armature	ischium with 3 spines, merus with 3 spines, carpus with 1 subdistal spine	ischium with 3 spines, merus with 5 spines, carpus with 1 subdistal spine	ischium with 3 spines, merus with 6 spines, carpus unarmed
Relative size of chelipeds	unequal	only 1 cheliped known	unequal
Length of pollex relative to upper palm	pollex of major P1 0.7 times upper palm length, that of minor P1 subequal to upper palm length	pollex 1.1–1.25 times upper palm length	pollex of major P1 0.8 times upper palm length, that of minor P1 1.5 times upper palm length
P1 carpus, dorsal surface armature	0–1 spine	2 spines	tuberculate on major P1, unarmed on minor P1
P1 propodus, dorsal margin armature	0–3 spines	7 spines	tuberculate on major P1, denticulate on minor P1

......continued on the next page TABLE 2. (Continued)

Characters/Species	G. polychaetes (K. Sakai, 1994 )	G. spinosissima ( Rathbun, 1906 )	B. thailandensis K. Sakai, 2015
P1 dactylus, dorsal margin armature	absent	absent	tuberculate on major P1, denticulate on minor P1
P2 merus, ventral margin armature	4 spines	4 spines	not known
P2 carpus, ventral margin armature	absent	1 spine	not known
P3–4 propodus and dactylus armature	corneous movable spines on P3–4 propodi only	absent	not known
P5 propodus and dactylus armature	corneous denticles on P5 propodus and dactylus	absent	not known
Telson, lateral margin armature	proximal spines variable (2 on right side, 4 on left side), and 1 distal spine	1 proximal spine followed by 1 spine at midlength	1 proximal and 5 distal spines
Telson, posterolateral margin armature	absent	3 pairs of spines	1 pair of spines
Uropodal endopod, lateral margin armature	2 spines	3 spines	1 spine
Uropodal exopod, lateral margin armature	5–6 spines	4 spines	5 spines
Nature of appendix masculina on male pleo- pod 2	uni-segmented, slightly longer than appendix interna	not known	tri-segmented, distinctly longer than appendix interna
Geographical distribution	Coral Sea off Queensland, Australia ( Sakai 1994 )	Hawaii ( Rathbun 1906 ), North of Buton strait, Indonesia (de Man 1925 ), Nuku Hiva, Marquesas Islands, French Polynesia ( Ngoc-Ho 2005 )	Andaman Sea, Straits of Malacca ( Sakai 2015 )
Bathymetric range	260 m	41–43 m, 75–94 m, 90–155 m	64–83 m
References (for morphological characters)	Sakai (1994 : figs 11A–F, 12B, F, 13A–F, H)	Rathbun (1906 : fig. 50a–b), Ngoc-Ho (2005 : fig. 1A–G)	Sakai (2015 : figs 3A–D, 4A, C–E, G)

In view of this, Guyanacaris K. Sakai, 2011 , is presently considered to represent 5 species— G. caespitosa ( Squires, 1979 ) , G. hirsutimana ( Boesch & Smalley, 1972 ) , G. keralam sp. nov. , G. polychaetes (K. Sakai, 1994 ) and G. spinosissima ( Rathbun, 1906 ) , with known geographical distribution in the Atlantic and Indo-Pacific Oceans. This genus differs from Acanthaxius Sakai & de Saint Laurent, 1989 , in having short supraocular spine, the presence of post-cervical carina on the carapace, dentate margins of pleura 1–2, angular to almost straight posterior margins of pleura 3–5, scaphocerite with mesial spine at base, and the presence of male pleopod 1 ( Sakai 2011 ; Poore 2020 ; present study). Morphological comparisons among the species of Guyanacaris and Bruceaxius are provided in Table 2 . Distribution. Southeastern Arabian Sea, India — 326 m .