TWOSYMPATRICSPECIES OF AXIUS FROMTHE NORTH-WEST ATLANTIC(DECAPODA,THALASSINIDEA, AXIIDAE)

BY

BRIAN KENSLEY 1/ Departmentof SystematicBiology, National Museum of NaturalHistory, Smithsonian Institution, Washington,D.C. 20560,U.S.A.

ABSTRACT Axiusserratus Stimpson,1852, is redescribed and illustrated, and its distribution based on 54 recordsof 68 specimensis recorded. The sympatric, and rarely recorded Axiusarmatus Smith,1881, isredescribed and illustrated for the Ž rsttime, based on six female specimens from Ž veseparate records.These two species are compared with the eastern Atlantic Axiusstirhynchus Leach,1815. Thethree species can be separated on the basis of the uropodal transverse suture, telsonic and pereopodalspination, and pereopod 4 sternitestructure.

RÉSUMÉ Axiusserratus Stimpson,1852 est redé crit et illustréet saré partition gé ographique est donné e, àpartirde 54 signalements de 68 spé cimens. L ’espèce sympatrique Axiusarmatus Smith,1881, rarementrencontré e, est redé crite et illustrée pourla premiè re fois, à partirde sixindividus femelles provenantde cinq stations sé paré es. Ces deux espè ces sont comparé es avec Axiusstirhynchus Leach, 1815,de l’ Atlantiqueoriental. Les trois espè ces peuvent ê trediffé rencié es par la suture transversale del’uropode, les é pinesdu telsonet des pé ré iopodes et enŽ n lastructuredu sternitedu pé ré iopode 4.

INTRODUCTION Thegeminate species Axius serratus Stimpson,1852, in the north-western Atlantic, and Axius stirhynchus Leach,1815, in the north-easternAtlantic, are bothlong-established, fairly frequentlyrecorded species. Thata third species of Axius occursin the western NorthAtlantic is oftenoverlooked. In fact, Axius armatus Smith, 1881,has onlybeen mentioned three times inthe literature since its description,and has neverbeen illustrated. Thelast mention(Sakai &De Saint Laurent,1989) questioned its positionin the genus Axius.Sixspecimens

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c KoninklijkeBrill NV ,Leiden,2001 Crustaceana 74(9):951-962 ° 952 BRIAN KENSLEY

(all females) ofthis species havebeen deposited in the collections ofthe National Museumof Natural History,includingone of Smith’ s syntypes.It was thought useful to Žll this gapin the knowledgeof the east coast U.S.shelf fauna,and to describe andillustrate the twowestern NorthAtlantic species, anddocument their distribution. Theholdings of A. serratus inthe SmithsonianInstitution, as well as those ofthe Museumof ComparativeZoology, Harvard (most ofwhich were collected byvarious NOAA National Marine Fisheries Service programs)were examined,on the off-chancethat specimens ofthe apparentlyrare A. armatus had beenmisidentiŽ ed. Unfortunately, no furtherspecimens werefound. Abbreviations:cl, carapacelength (posterior orbital marginto posterior cara- pacemargin); MCZ,Museum of Comparative Zoology, Harvard University; NOAA,National Oceanicand Atmospheric Agency; USNM, UnitedStates Na- tional Museum,Smithsonian Institution; VIMS,Virginia Institute ofMarine Sci- ences.

SYSTEMATICS

Axius armatus Smith, 1881(Ž gs. 1, 2,4)

Axiusarmatus Smith,1881: 433; De Man, 1925: 3, 9,11. ?Calocaride Sakai& DeSaint Laurent, 1989: 101.

Materialexamined. — Syntype,USNM 35391, cl13.2 mm (eggspresent in ovaries), R/ V“Fish Hawk”sta. 878, off Martha’ s Vineyard,Massachusetts, 39 ±550N 70±5401500W,260m, 13 September 1880.— USNM 174450,ovigerous cl8.1mm (damaged),off South Carolina, 32 ±300N 78±290W, 218m, coll. K. Shaw,6 June1978. — USNM 174451, cl6.2 mm, offSouth Carolina, 32 ±300N 78±290W,218m, coll. K. Shaw,6June1978. — USNM 243489,2 cl5.6mm, 6.9mm, R/V“Fish Hawk”sta. 949, off Martha’ s Vineyard,Massachusetts, 40 ±030N 70±310W,183m, 23 August 1881. —USNM 306381, cl7.0 mm, George’s Bank,40 ±2201200N 68±3001200W,108m, R/ V“Oceanus” cruiseM10, sta. 12, 13 November1983. Description.— Female syntype.Carapace (Ž gs. 1A, B, 2A)with rostrum reachingto distal edgeof antennularpeduncle article 2,armedwith 3to 6teeth (4in 3specimens), posteriormost in supraocularposition, but not enlarged, rostral marginproduced posteriorly as Žnelateral carina; submediancarina aŽneridge anteriorly recurved,lacking teeth; mediancarina bearing2 or3 teeth (3in one specimen),unarmed posterior totubercle. Sternal plate betweenbases ofpereopods 4(Žg. 2C) with lateral angerounded. Abdominal pleura (Ž g. 1C) ventrally broadlyrounded, that ofabdominal somite 2broadest.Telson (Ž g. 1D)about 1.5 times longerthan basal width;lateral margins with4 serrations, posterior margin convex,with small spine at midpoint;dorsal surface with 3spines onleft half,2 on right. N.W.ATLANTIC AXIUS 953

Fig. 1. Axiusarmatus Smith,1881, syntype USNM 35391.A, carapacein lateral view ,scale D 5mm; B,anteriorcarapace in dorsal view; C, abdomen,telson and right uropod in lateral view; D,telsonand right uropod in dorsal view; E, pereopod1 smallercheliped; F ,pereopod1 larger cheliped;G, pereopod2; H, pereopod3; I,pereopod4; J, pereopod5; K, maxilliped3; L, pleopod1; M,pleopod2.

Antennularpeduncle reaching to midlengthof antennal peduncle article 4; agella subequalto lengthof carapace. Antennal peduncle (Ž g. 1A) article 3 with strongdistal spine onupper margin, small distal spine onventral; acicle slender,dagger-shaped, reaching two-thirds alongarticle 4; article 5aboutone- thirdlength of article 4;agellum abouttwice carapacelength. Maxilliped 3(Žg. 1K),ischium, merus,carpus, propodus, and dactylus bearingdense band of setae 954 BRIAN KENSLEY

Fig. 2. Axiusarmatus Smith,1881, USNM 306381.A, carapacein lateral view ,scale 5 mm; D B,pereopod1 largercheliped; C, sternitebetween pereopod 4 bases;D, Axiusserratus Stimpson, 1852,USNM 20864,sternite between pereopod 4 bases;E, Axiusstirhynchus Leach,1815, USNM 252600,sternite between pereopod 4 bases. onlowermargin; merus with 3teeth onventral marginincreasing inlength distally; carpuswith toothat posterodistal angle; crista dentata ofischium having20 teeth. Pereopod1, larger cheliped(Ž gs. 1F ,2B),ischium lackingarmament; merus withupper margin strongly carinate, lowermargin bearing 4 teeth inproximal half; propoduswith upperand lower margins stronglycarinate, uppermargin endingdistally in single small tooth,Ž xedŽ ngershorter thandactylus, probably regenerating,with single strongtriangular cuspon cutting edge. Pereopod 1, smaller cheliped(Ž g. 1E), merus withsingle toothon carinate uppermargin, 4 proximalteeth onlower margin; upperand lower margins ofpropodus strongly carinate, uppermargin with single distal tooth;cutting edgeof Ž xedŽ ngerwith tinyproximal serrations, Žnecorneousstiff spine-like setae distally; cutting edge ofdactylus with Žnecorneoussetae. Pereopod2 (Žg. 1G), merus with 4teeth and numerouselongate setae onlower margin; carpusand propodus with numerous setae alongupper and lower margins; cuttingedges of chela Žngersbearing short spine-like setae. Pereopod3 (Žg. 1H), carpus and propodus bearing elongate setae alongupper and lower margins; dactylus with Žnesetae alonglower margin. Pereopod4 (Žg. 1I), propodus with distal denseoblique clump of cleaningsetae; dactylus bearingrow of about 7 corneousspine-like setae onlateral surface. Pereopod5 (Žg. 1J), propodus with numerous setae onlower distal margin; N.W.ATLANTIC AXIUS 955 dactylus twisted, withsetae alongupper margin. Pleopod 1 (Žg. 1L) consisting ofsingle slender setose ramus.Pleopods 2-5 (Ž g. 1M) with appendixinterna at midpointof mesial marginof endopod. Uropodal lateral ramus (Žg. 1D),lateral marginwith about9 serrations distally,slender articulating spine at angleof transverse suture,7 spines alongtransverse suture; uropodalmesial ramus with 3serrations distally onlateral margin,strong spine at distal angle,7 spines along middorsal ridge.

Branchial formula:

Maxilliped1 – – epipodite – – Maxilliped2 –podobranch epipodite,1 arthrobranchs – C Maxilliped3 setobranch,podobranch epipodite,2 arthrobranchs – C Pereopod1 setobranch,podobranch epipodite,2 arthrobranchs – C Pereopod2 setobranch,podobranch epipodite,2 arthrobranchs,1 pleurobranch C Pereopod3 setobranch,podobranch epipodite,2 arthrobranchs,1 pleurobranch C Pereopod4 setobranch, epipodite,2 arthrobranchs,1 pleurobranch Pereopod 5 – – – – –

Variation. —Thelateral rostral teeth forthe three undamagedadditional specimens available vary:4/ 3,4/ 4,5/ 6(syntype4/ 5),but all specimens have twoteeth onthe mediancarina anterior tothe tubercle.The larger chelipedof pereopod1 inthe USNM306381female, has asmall toothon the lowermargin ofthe propodus,and a strongtooth on the lowermargin of the ischium, neither of whichare present in the syntypicfemale. Distribution. —Massachusetts to SouthCarolina, depth range 108-260 m. Remarks.— Thefollowing features place this species in the genus Axius: uropodallateral ramus withtransverse suture; pereopodalepipods present; ros- trum notspike-like, longerthan eyes, dentate; maxilliped 3exopodnot clearly bent; pleopods2-5 with appendixinterna; antenna2 acicle (scaphocerite) simple; pleurobranchspresent; supraocularspines absent (see Poore,1994: 97). In addi- tion,the three species mentionedhere all havean unarmed submedian carina of the carapace,with the anterior endcharacteristically exedtowards the midline. Smith (1881)mentions “ animperfect male specimen : : :”alongwith the de- scription ofthe female. This male syntypehas notbeen located inthe USNM collections.

Axius serratus Stimpson,1852 (Ž gs. 3, 4) Axiusserratus Stimpson,1852: 222; Smith, 1879: 55, pl. 10 Ž gs.4, 4a; 1881: 435; Rathbun, 1929: 25,Ž g.32; Williams, 1974: 17, Ž g.46A, B; Pembertonet al., 1976: 790; Williams & Wigley, 1977:3, 4, 5,8, 16; Williams, 1984: 185, 187, Ž g.130.

Typelocality. — Scituate,Massachusetts Bay, 20 fathoms (36.6 m). Smith (1879) mentions Stimpson’s driedtype specimen in the Peabody Academy of Science, Salem, Massachusetts. 956 BRIAN KENSLEY

Materialexamined. — USNM 20864,1 cl25.0mm, George’s Bank,coll. Capt. J. Getchell, 1879.— USNM 20865,1 cl 13.0 mm, 1 cl15.6mm, R/V“FishHawk” sta. 849, off Newport, RhodeIsland, 1880. — USNM 31450,1 cl18.1mm, R/V“FishHawk” sta. 1613, Long Island Sound,19 m [damaged].— USNM 31451,1 cl12.1 mm, R/V“FishHawk” sta. 1804, Long IslandSound, 28 m. — USNM 39960,1 ovigerous cl27.3 mm, George’s Bank,coll. U.S. FishCommission. — USNM 40509,1 cl22.9 mm, George’s Bank,coll. Capt J. Getchell, 1879[damaged]. — USNM 61545,3 ovigerous cl25.2 mm, 2damaged,from stomach of codtaken off Nantucket, Massachusetts, coll. February 1928. — USNM 80514,1 ovigerous cl 28.5mm, SheepscotRiver, Barters Island, Maine, coll. L. W.Scattergood,24 October 1944. — USNM 80518,1 cl23.3mm [dryspecimen, damaged], off New Harbor,Muscongus Bay, Maine, 54m, coll. L. W.Scattergood,10 March 1944. — USNM 95937,1 cl12.5 mm, offWoods Hole,Massachusetts, 44 ±200N 67±430W,coll.17 August1953. — USNM 173737,1 cl 10.4 mm, Seabrook,New Hampshire,coll. S. Grabe.— USNM 202189,1 juvenile,damaged, off New Jersey, 39±1902400N 73±1001800W,64m, coll. VIMS 11February 1977. — USNM 202190,2 juveniles cl3.8 mm, 4.0mm, offNew Jersey,38 ±4204800N 73±2402400W,77m, coll. VIMS 9February 1977.— USNM 202191,1 juvenilecl 2.9 mm, offNew Jersey,38 ±4300000N 73±2402400W, 78 m, coll.VIMS 11November 1976. — USNM 202192,1 cl6.7 mm, offNew Jersey,39 ±2603600N 73±0904800W,58m, coll. VIMS 15November1976. — USNM 202193,1 juvenilecl 2.3mm, off New Jersey,39 ±2102400N 73±1100000W,62m, coll. VIMS 15November 1976. — USNM 202194,2 juveniles,damaged, off New Jersey,38 ±4203600N 73±2401800W,75m,coll. VIMS 18August1976. — USNM 202195,1 juvenile,damaged, off New Jersey,38 ±4401200N 73±2503600W,70m, coll. VIMS 18August1976. — USNM 202196,1 cl4.9 mm, offNew Jersey,39 ±0205400N 73±4700600W, 51 m, coll.VIMS 17June 1976. — USNM 202197,1 juvenilecl 4.5 mm, offNew Jersey,39 ±0205400N 73±4700600W,51m, coll. VIMS 17June 1976. — USNM 202198,1 juvenilecl 3.9 mm, offNew Jersey, 39±0205400N 73±4700600W,51m, coll. VIMS 17June1976. — USNM 202199,1 juvenilecl 3.2mm, offNew Jersey,39 ±0205400N 73±4701200W,49m,coll. VIMS 21February1976. — USNM 213543, 1 cl8.4 mm, NOAA sta.OCS III-30A.— USNM 213544,1 damaged,NOAA sta. LISI-27,Long Island Sound, coll. 15 August 1972. — USNM 213545,1 cl11.5 mm, NOAA sta.I-67, Baltimore Canyon, coll. 24 May 1974. — USNM 213546,1 ovigerous cl 26.2 mm, BaltimoreCanyon, coll. NOAA. —USNM 213547,1 cl24.5 mm, NOAA sta.AL 81-0718 May1981. — USNM 243488,1 cl14.2 mm, IpswichBay, Massachusetts, 19 December 1961. — USNM 258886,1 cl7.2 mm, BLM sta.3-6e, Nantucket Shoal, George’ s Bank,40 ±260N 70±030W, 75m,18 August 1977. — USNM 258887,1 juveniledamaged, BLM sta.3-19A, George’ s Bank, 40±340N 67±450W,98m,August 1977. — MCZ 29101,1 cl21.5 mm, 16-18miles E ofEastern Point,Cape Ann, Massachusetts, 40-55 m, 18 October1961. — MCZ 29102,1 ovigerous cl 27.3 mm, “DelawareII” cruise76-6, sta. 8, 37m,8 April1976. — MCZ 29103,1 cl24.4 mm, 43 ±310N 66±260W,86m, 17 July 1965. — MCZ 29104,1 cl14.3 mm, 41 ±00N 71±300W,55m, 19 June 1962.— MCZ 29105,1 cl19.3 mm, 41 ±170N 71±00W,37m, 17 August1965. — MCZ 29106, 1 cl 6.8 mm, 41±60N 69±170W,7December1955. — MCZ 29107,1 cl8.8mm, fromhaddock stomach.— MCZ 29108,1 damaged, 42±150N 70±00W,100m, 11 December 1958. — MCZ 29110, 1 cl7.0 mm, nodata.— MCZ 29111,1 14.5 mm, 43±100N 66±400W,114m, 24 August 1965.— MCZ 29113,1 cl12.2 mm, 41 ±100N 71±00W,33m, 17 August1965. — MCZ 29114, 1 cl11.5 mm, 40 ±270N 67±530W,128m, 8 November1966. — MCZ 29115,1 cl 18.0 mm, 40±300N 67±580W,115m, 5 April1965. — MCZ 29434,1 cl24.2mm, 43 ±360N 67±330W, 220 m, 16November1964. — MCZ 29435,1 cl22.5 mm, 43 ±370N 66±420W,122m, 13 October1965. —MCZ 29436,1 ovigerous damaged,Plymouth, Massachusetts, January 1900. — MCZ 29437,1 cl17.0mm, 41 ±60N 70±150W,24m,4 November1966. — MCZ 29439,2 cl14.5mm, 15.3mm, 44±28:30N 67±15:20E,116m, 11 August1963. — MCZ 29440,1 cl24.7 mm, 44 ±400N 66±160W, 132m, 13 October 1965. — MCZ 29441,1 ovigerous cl22.0 mm, 44 ±200N 67±420W, 68 m, 17August1953. — MCZ 29442,1 cl21.5mm, 43 ±20:40N 66±130W,61m, 10 August1963. — N.W.ATLANTIC AXIUS 957

Fig. 3. Axiusserratus Stimpson,1852, USNM 80514.A, carapacein lateralview ,scale 10 mm; D B,anteriorcarapace in dorsal view; C, abdomen,telson and right uropod in lateral view; D, telson andright uropod in dorsal view; E, pereopod1 smallercheliped; F ,maxilliped3; G, pereopod1 largercheliped; H, pereopod2; I,pereopod4; J,pereopod5; K, pereopod3; L,USNM 20864,male pleopod2; M,USNM 20865,telson and right uropod in dorsal view . 958 BRIAN KENSLEY

MCZ 29443, 1 cl16.2 mm, “AlbatrossIV” cruise 74-4, sta. 217. — MCZ 29444,1 cl 18.0 mm, 44±30N 63±230W,198m, 28 April 1971. — MCZ 29445,1 cl25.5mm, 6ovigerous cl 24.0mm, 25.2mm, 25.3mm, 25.7mm, 26.9mm, 27.5mm, 3 cl18.3mm, 23.8mm, 27.0mm, BlockIs. Sound, 42 m, coll. 10 February1959.

Description.— Carapace(Ž g. 3A,B), rostrum reachinganteriorly to antennular pedunclearticle 3,with 4-6lateral teeth; rostral margins producedposteriorly as unarmedcarinate lateral carinae; medial carina well deŽned, sharp, reaching fromanterior rostrum tosubmedian carinae; latter poorlydeŽ ned, unarmed, with anterior extowards midline. Small toothon anterior marginof carapace in antennalregion. Sternal plate betweenbases ofpereopods4 (Žg. 2D),lateral ange spinose.Abdominal pleura (Ž g. 3C) ventrally rounded,pleuron of abdominal somite 2broadest.Telson (Ž g. 3D,M), basal widthslightly greater thanmidlength, posterior marginconvex with small toothat midpoint; 1pair ofsmall spines submediallyon dorsal surface. Antennular agella subequal,about two-thirds carapacelength. Antennal pe- duncle(Ž g. 3A) article 3withstrong dorsodistal taperingacute lobe,small acute spine ventrodistally; acicle reachingbeyond distal marginof article 4,acute, mesial marginsinuate; article 5short,just less thanhalf lengthof article 4.Maxilliped 3 (Žg. 3F), basis with strongventrodistal spine; lowermargins ofischium, merus, carpus,and propodus bearing dense band of elongate setae, setae also present along dorsal marginof carpus, propodus, and dactylus; merus with strongventrodistal spine,and smaller spine at aboutmidpoint of lowermargin; exopodreaching just beyonddistal marginof merus. Pereopod 1, larger cheliped(Ž g. 3G), ischium with 2rowsof irregular tubercles onlowersurface; ischium with 3teeth onlowermar- gin; carpuswith submarginalcrenulate ridgenear lower margin; propodalpalm slightly longerthan Ž ngers,with submarginal crenulate ridgealong lower mar- gin,cutting edgeof Ž xedŽ ngerwith several small and2-3 larger triangular tuber- cles; dactylus with strongsubmarginal ridge dorsally, cutting edgeŽ nelycrenulate. Pereopod1, smaller cheliped(Ž g. 3E),ischium with2 rowsof irregular tubercles onlowersurface; ischium with4 teeth alonglower margin; propodalpalm about one-fourthshorter thanŽ ngers,with crenulate submarginalridge near lower mar- gin,cutting edgeof ŽxedŽ ngerwith several irregular lowtubercles; dactylus with ridgeon lateral surface neardorsal margin,cutting edgeŽ nelycrenulate. Pereo- pod2 (Žg. 3H),ischium with fewirregular tubercles onlower surface; merus with bandof elongate setae onlowermargin; carpuswidening distally; propodusbroad, attened,with bandof elongate setae onlower margin; cuttingedges of Ž ngers with Žneshort spine-like setae; dactylus somewhat attened.Pereopod 3 (Žg. 3K), propodsovate,  attened,bearing numerous clumps ofelongate setae; dactylus with numerousclusters ofshort setae. Pereopod4 (Žg. 3I),propodus with densepad of stiff groomingsetae distoventrally.Pereopod5 (Žg. 3J), propodus with distoventral N.W.ATLANTIC AXIUS 959

Fig.4. Distributionof Axiusarmatus Smith,1881 and Axiusserratus Stimpson,1852 in thenorth- westAtlantic. bandof densegrooming setae, broadlyrounded lobe projecting from ventrodistal angle; dactylus twisted, with densesetae alongupper margin. Pleopod 1 in both sexes consisting ofsingle slender setose ramus.Pleopod 2 inmale (Žg. 3L)with slender rod-shapedappendix masculina bearingnumerous Ž nesetae distally; ap- pendixinterna abouttwo-thirds lengthof appendix masculina. Uropodallateral 960 BRIAN KENSLEY ramus (Žg. 3D), distolateral marginwith few irregular serrations; notransverse suture present; mesial ramus with single toothat distolateral angle,single tooth proximallyon dorsal roundedridge, single toothat aboutmidpoint of distal mar- gin.

Branchial formula:

Maxilliped1 – – epipodite – – Maxilliped2 –podobranch epipodite1 arthrobranch – C Maxilliped3 setobranchpodobranch epipodite2 arthrobranchs– C Pereopod1 setobranchpodobranch epipodite2 arthrobranchs– C Pereopod2 setobranchpodobranch epipodite2 arthrobranchs– C Pereopod3 setobranchpodobranch epipodite2 arthrobranchspleurobranch C Pereopod4 setobranch– epipodite2 arthrobranchspleurobranch Pereopod 5 – – – – pleurobranch

Variation. —Teethon the lateral margins ofthe lateral andmesial uropodal rami andthe dorsal ridgeof the mesial ramus varywith age. Y oungerspecimens (see Žg.3M)can have up to 6teeth onthe lateral marginof the lateral ramus,2 or 3teeth onthe lateral marginof the mesial ramus,and up to 6 teeth onthe dorsal ridgeof the mesial ramus.These teeth are oftenworn down or lost in older,larger specimens. Thelateral marginof the telson usually has onesmall tooth,but 2 are occasionally seen. Remarks.— TableI comparesthe three NorthAtlantic species of Axius, separating them onŽ vefeatures. Just onsimilarity ofappearance, A. serratus and A. stirhynchus wouldseem to beclosely related, the carapace,rostrum, and pereopod1 chelipeds beingvery similar. Thetwo species also reacha similar size at maturity. Axius armatus is amuchsmaller species, with asomewhatdifferent overall appearance;the twoteeth onthe mediancarina immediately separate it from A. serratus and A. stirhynchus .Theloss ofa transverse suture onthe lateral ramus ofthe uropod(a widespreadplesiomorphic feature in the Axiidae)in A. serratus suggests that this species is somewhatmore advanced over the eastern Atlantic A. stirhynchus . A. armatus,with sevenor eight spines onthe transverse suture,and being somewhat more spinose generally,does not appear to beas closely related to either ofthe otherspecies. Axius serratus reaches populationsizes (upto 9persquare meter) that canhave amajor impact onbottom sediment turbation.Pemberton et al. (1976)found the shrimps burrowingto adepthof 3 min the Strait ofCansooff Nova Scotia. Their excavationsresulted inthe massive buryingand recycling of bottom pollutants in the sediments. Axius serratus wouldseem to bepreyed on by bottom-feeding Ž sh,as two recordsgiven above are ofspecimens fromthe gutof acodand haddock, while N.W.ATLANTIC AXIUS 961

TABLE I Morphologicalfeatures separating three North Atlantic species of Axius

A. armatus A. serratus A.stirhynchus Smith, 1881 Stimpson,1852 Leach, 1815 Lateralramus of Transversesuture Transversesuture Transversesuture uropod with7-8 spines lacking with3 spines Telsondorsal spines 4 2 2 Mediancarina of 2 spines Unarmed Unarmed carapace Pereopod1 merus 1dorsalspine Unarmed Unarmed Pereopod4 sternal Rounded Spinose Acute plate,lateral  ange Ovigerousfemale, 8.1-13.2 mm 22.0-28.5mm 24.1 mm carapacelength

Smith (1879:55) mentions aspecimen fromthe gutof a oundertaken off Massachusetts. Ovigerousfemales of A. serratus havebeen taken in January ,February,April, August,and October, but with onlysix separate records,it is difŽcult to discern anyseasonality in breedingcycle ofthe species. Distribution. —NovaScotia toMaryland, depth range 19-220 m. From the material listed above,of the 34recordsfor which depth is known,25 are fromless than 100 m.

ACKNOWLEDGEMENTS

IthankMs. Ardis Johnsonfor the loanof MCZ material. Iam grateful to William Moser andMarilyn Schotte,Department of Systematic Biology,National Museumof Natural History,who prepared the mapused in Žg.4. Dr .Rafael Lemaitre reada draft ofthis paper;I am grateful forhis useful comments and suggestions.

LITERATURE CITED

LEACH,W.E., 1815.A tabularview of the external characters of four classes of animals, which Linnéarranged under Insecta; with the distribution of thegenera and species. Transactions of theLinnean Society of London, 11: 306-400. MAN, J. G. DE,1925.The Decapoda of theSiboga-Expedition. Part VI. The Axiidae of theSiboga Expedition.Siboga Expedition Monograph, 39a (5): 1-127. 962 BRIAN KENSLEY

PEMBERTON,G.S.,M.J.R ISK & D. E. BUCKLEY,1976.Supershrimp: deep bioturbation in the Straitof Canso,Nova Scotia. Science, New York, 192 (4241):790-791. POORE,G.C.B.,1994.A phylogenyof thefamilies of Thalassinidea (Crustacea: Decapoda) with keysto families and genera. Memoirs of theMuseum of Victoria, 54: 79-120. RATHBUN,M.J.,1929.Canadian Atlantic fauna. 10. Arthropoda.10 m. Decapoda: 1-38. (Biologi- calBoard of Canada, Atlantic Biological Station, St. Andrews, N.B.). SAKAI, K. & M. DE SAINT LAURENT,1989.A checklist of Axiidae (Decapoda, Crustacea, Thalassinidea,Anomura), with remarks and in addition descriptions of one new subfamily, elevennew genera and two new species. Naturalists, 3: 1-104. SMITH,S.I.,1879.The stalk-eyed crustaceans of the Atlantic coast of North America, north of CapeCod. Transactions of the Connecticut Academy of Artsand Sciences, 4 (5):247-253. ——,1881.Preliminary notice of theCrustacea dredged, in 64 to325 fathoms, off the south coast ofNew England,by the United States Fish Commission in 1880. Proceedings of the United StatesNational Museum, 3: 413-452. STIMPSON, W., 1852. [: : :descriptionof a newcrustacean belonging to the genus Axius, of Leach: : :].Proceedingsof the Boston Society of Natural History, 4:222-223.[Paper lacks formaltitle.] WILL IAMS,A.B.,1974.Marine fauna and  oraof the northeastern United States. Crustacea: Decapoda.NOAA TechnicalReport, NMFS Circular, 389: 1-50. ——,1984.Shrimps, lobsters, and crabs of the Atlantic coast of the eastern United States, Maine to Florida:1-550. (Smithsonian Institution Press, W ashington,D.C.). WILL IAMS,A.B.&R.L.W IGLEY,1977.Distribution of decapod Crustacea off northeastern UnitedStates based on specimens at the Northeast Fisheries Center, Woods Hole, Massa- chusetts.NOAA TechnicalReport, NMFS Circular, 407: 1-44.

Firstreceived 24 February2001. Finalversion accepted 1 May2001.