Description of an apparently new species of <I>Gasterosteus (G. atkinsii</I>) from the Schoodic Lakes, Maine

PROCEEDINOS

OF

UNITED

STATES

NATIONAL MUSEUM.

67

I>ESCRHI»TI©IV

OF

ATV

APPARENTIiY NEW SPKCIE8 OF

«-ASTEU-

OSTEUS

(G.ATfCINSai)

FROM THE

St!MOO»a€ILAECES,

MABNE.

By TARI.ETOIV H. BEAM.

In alargecollectionoffishes sent to theUnitedStatesNationalMu- seum,in 1878,byMr.C.Gr.Atkins,an assistant ofthe United States FishCommission,weresixspecimensof a sticklebackwhichappearsto be undescribed, and for which I j^ropose the

name

given above,asa slightrecognition ofMr. Atkins's services asacollectorandasanorig- inalinvestigator into the rei)roductive habits of imiiortantfishes.

GasterosteusAtMnsii resembles in form and coloration G.pungitius ratherthantheperhapsmorecloselyrelated G.aculeatus. It

may

beat oncedistinguishedfrom all the other easternAmericanspeciesby(1)

thepresenceofabont fitteen lateral plates,which rapidlydiminish in size after the fonrtli, and(2) its long ventral spines,which nearlyor quitereach thevent. Theplates are quite unlikethoseof G.semiarma-

ti(S,beingso thinandposteriorly sosmall that theyareinconspicuous.

Forthe purposeofdescription Ihave selected the individualwhose catalogue-number is 22492 a (collector'snumber,3013). The extreme lengthof thisspecimenis35millimetres,anditslengthtotheorigin of the middle caudal rays is30millimetres,whichisthe basis ofcompari- sonforallthe other measurements.

Theheightof thebodyat the ventrals (.21)equals3times thelength of thenpperjaw(.07),and 3 timesthe distancebetweenthe eyes(.07).

Its greatestwidth(.11)equalsthelongdiameteroftheorbit(.11). The leastheight ofthetail (.04)equals the lengthofthe antecedent anal spine(.04)andone-halfthe lengthofthe snout(.08). Thelengthofthe caudal peduncle(.13)somewhatexceeds the widthofthehead(.12).

Thelengthofthehead(.31)equals3 times the lengthofthe mandi- ble(.10).

The

lengthofthe snout equals thatof the operculum (.08).

Thelengthoftheupper jaw(.07)equalsthedistancebetween the eyes andone-halfthe lengthofthepost-pectoral plate(.14). The lengthof themandible(.10) iscontained 10 times in thetotallengthandequals twice the lengthoftheantecedentspine oftheseconddorsal(.05). The long diameterofthe orbit ^is contained 2f times ⁱⁿ the lengthofthe headand9timesinthetotal length.

Theteethare as intheothermembersofthe family.

Thespinousdorsalhastwospines ofequallength. Itsdistancefrom thesnout (.37)equals shghtlymorethan twice the lengthofthe pecto- ral(.18). Thelengthofthetwospines (.12)equalsthat of thefirstand longestrayoftheseconddorsal(.12)andofthe anal(.12). The spines are inastraightline, andwitheach isconnected adelicatemembrane.

Thedistance of theanal fromthe snout(.06)equals 6 timesthe long diameteroftheorbit. Itslengthofbase(.18)equals2J times^thelength of theoperculum.

The

lengthofthe anecedent analspine (.04) is con- tained 3timesinthat ofthefirstandlongestray(.12).

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^STATES

NATIONAL MUSEUM.

Tlie lengthof themiddle caudal rays (.16|) ^iscontainedG times in thetotallength.

Thecaudalisslightly forked, almost trimcate

when

expanded.

Thepectoral is composedof tenrays. Its distancefrom the snout (.34)isa^littlelessthan twiceits length (.18). Itextendsto the mid- dle oftheintervalbetweenthetwodorsals.

The

lengthof the post-pec- toralplate(.14) equals twice that ofthe upper jaw,anditswidth(.04)

equalsthelengthoftheantecedent analspine.

The

ventral consists ofone spine and oneray. Its distance from the snout (.45) equals 4J times the length of the lower jaw. The spineextends beyond theendofthe pubic bones,reaching almost or quite tothevent. Its length (.19) exceedsthat of the pectoral(.18).

Itisverystrongly serratedon itsouterandfinelyonitsinner margin.

Theoriginofthe\'entralisslightly in advanceofthe perpendicularlet fallfrom the seconddorsal spine.

Eadial formula: B. Ill; D.II,I,10-12; A.I, 8-9; C,

+

¹²

+;

^P.

10^; V.I,1.

Color.

— Dark

bandscross thebody just as in G. pungitius,whichit strongly resembles. Theground-colorofthebodyinthe alcoholicspeci-

mensisalmostflesh-color; themajori^artoftheheadis silvery,as are thebreastandthebelly.

Table of Measurements.

Currentnumberofspecimen.

Locality

22,492 a.

Schoodic Lakes,Me.

Millime- lOOthsof trea. length.

Extremelength.

Lengthto originof middle caudal rays.

Body.

Greatest height GreatestwiJth Heightatventrals Least height oftail Lengthofcaudal peduncle Heftd:

Greatestlength Greatestwidth Widthofinterorbitalarea Lengthofsnout Lengthofoperculum Lengthofupperjaw Lengthofmandible Distancefromsnoutto orbit Diameteroforbit Dorsal(spinous)

:

Distancefrom snout Lengthoffirstspine Lengthofsecond spine Dorsal(soft)

:

Lengthofantecedent spine Lengthoffirstray Anal:

Distancefrom snout Lengthof base Lengthoffirstspine Lengthoffirstray Lengthof longestray Caudal

:

Lengthofmiddle rays

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Table ofMeasurements—Cont'mued.