Pogonophora from the Northeastern Pacific: First Records from theGulf of Tehuantepec, Mexico

OLUWAFEYISOLA S. ADEGOKE1

N ORTHEASTERN PACIFIC records of species ofthe Phylum Pogonophora Johansson, 1937 arefew. In all, eight species have been recorded.Th e first was by Kirkegaard ( 1956a, 196 1)who described Lamellisabella iuanoui from theGulf of Panama. In two successive records,Ivanov (1 961, 1962) described Galatbealinnmbracbiosnm, and H eptabrachia ctenopbora andH . canadensis, respectively, from the west coastsof Canada and Or egon. Hartm an (1 961) re­corded abundant occurrences of Siboglinnmoeleronis H artman from the La Jolla Canyonoff the coast of southern California. Southward(1 962) next described Galatbealinnm arcticumfrom Arctic waters off the northern coast ofYukon, Alaska ; and more recently, Cutler(1965) described two new species of Sibog­linum, S. albatrossianum and S. ectmdo ricum,and an undetermined specimen, from collec­tions dredged off Cape San Francisco, Ecuador ,by the U. S. Fish Commission steamer "Alba­tross" in 1888.

The occurrences of a few dark-brown, cylin­drical collar segments, measuring about 2.9­4.0 mm across, and 3.3 mm long, from WestCortes, East Cortes, and Long Basins, and fromthe San Diego Tr ench, were recorded by Hart­man and Barnard (1 960). These were laterreferred to the genus Galatb ealinum Kirke­gaard, 1956 by Hartman (1961:546), whoalso mentioned a new record of another speciesof Siboglin1J111 closely resembling S. oeleronisfrom "Velero IV" Station 7231, off SanEugenio Point, Lower California, Mexico.

ACKNOWLEDGMENTS

The materials on which this study is basedwere made available to the author by the kindpermission of Professor J. Wyatt Durham and

1 Department of Paleontology, Univ ersity of Cali­forni a, Berkeley, Californ ia. Present address: Cali­forn ia Inst itute of T echnology, Pasadena, California.Manuscript received April 18, 1966.

Mr. J. H. Peck, Jr. of the Museum of Paleon­tology, Un iversity of Califo rnia, Berkeley. Theauthor is grateful to Dr. Gwyn Thomas of theGeology Department, Impe rial College, Lon­don, for calling his attention to the fact thatthe specimens might repre sent an undescribedspecies, and to Professor H . A. Lowenstam ofthe California Institute of Technology, Pasa­dena, for his critical readin g of the manuscriptand for his many helpful suggestions. Theillustrations were prepared by the writer andJur rie J. van der W oude of the CaliforniaInstitute of Technology. The author 's wife,Adekun bi Adegoke, assisted in preparing themanuscript.

MATERIAL STUDIED

Th e new species, Galatbealinnm mexicannmsp. nov., described below is the fourth speciesto be described in the genus Galatbealinum: Itwas dred ged by the Vermillion Sea Expedition(1958) from a depth of 3531-3603 m in theGulf of Tehuan tepec, Mexico (Univ. Calif.Mus. Paleo. locality B-7469 ) . It is the firstpogonophoran record from the Gulf of T e­huantep ec.

Onl y the dried remains of the tubes arepreserved. These dark brown tubes are thick­walled and rigid , and have preserved their truecylindrical shape. They taper slightly and uni ­formly, have an average diameter of over2.0 mm, and are prominently subdivided alongthe ent ire length into segments, each abouttwice as long as the average diameter of thetube. The exterior of the tubes is covered by athin, feltlike layer composed of fine and coarsefibers. The coarse fibers are more prominentand more numerous near segmental junct ions.These character s place this species within thegenus Galatb ealinum as defined by Kirkegaard(19 56) and Ivanov (1963) .

Although most Recent pogonophoran generaand species are established primarily on the

188

Pogonoph ora from Tehuantepec- ADEGOKE

basis of soft part anatomy, remains of well­preserved tubes are also known to be sufficient lyreliable for "specific diagnosis" (see H artman,1961:546 ; Ivanov, 1963 :120) . T he latterauthor firmly established the validity of thiscontent ion by constructing a dichotomous keyfor the identification of most Recent pogono­phoran species from remains of th eir tubes(Ivanov, 1963:456-461) . T he characte rs ofthe tubes described and figured in thi s reportreadily distinguish them from the three pre ­viously described species of Galatbealinnm ; Itis hop ed that, in the future, preserved materialfrom the same area will provi de data on th enature of the soft part anatomy of th e newspecies.

SYSTEMATIC DESCRIPTION

Phylum POGONOPHORA Johansson, 1937Order THECANEPHRIA Ivanov, 1955Family POLYBRACHIIDAE Ivanov, 1952Genus Galatbealinum Kirkegaard , 1956

Galatbealinnm Kirkegaard , 1956, GalatheaRept. 2:79-83.

TYPE SPECIES: Galatbealinnm brnnni K irke­gaard.

Galatbeallnum mexlcanum sp. nov.

Figs. 1-7

DIAGNOSIS: Galatbealinnm with elongate,cylindrical, segmen ted tube; circular cross-sec­tional outline; average tube diameter 2.0-2.5mm ; covered along entire length by thin , felt­like layer of fine and coarse fibers; ind ividualcoarse fibers at segmental junction about 15­22f! thick; segment length approximately twicethe diameter.

DESCRIPTION: This species is represented byfragments of dried tubes only. The tubes arebrownish-gray to dark-gray, elonga te and slen­der. Th e longest fragment (holotype, Fig. 1)is 147.5 mm long. Maximum diameter 2.5 mm,minimum diameter 1.96 mm. Externally, thetube is divided into num erous prominent seg­ments (see Figs. 1- 6). Th ese segments have acircular cross-sectional outline and are of ratherun iform length , each measur ing 3.8-4.9 rnm,The widened funnel-like fr ills that are prom­inently shown at the nodes of the described

189

F IG. 1. Galathealinum mexicanum Adegoke sp.nov. Tu bes from Univ. Calif . Mus. Paleo. localityB-7469, Gu lf of Tehuantepec, Mexico. Holotype,UC M P 32882. Entire specimen showing long, curved,segmented tube, X %.

species of Galatb ealinnm are only poorly p re­served on the dried tubes of the present species(Figs. 3, 7). Th e coarse fibers genera lly asso­ciated with these frills are well develop ed, how­ever, and are more abundant at the nodes thanin the much longer internodes. The exterior ofthe tube is coated by a thin, friable, feltlikelayer, mostly composed of numerous, very fine,light- brown fibers, and few, coarse, redd ish­brown, glistening fibers. T he latter also pen e­trate the tube wall and appear as faint ridges enthe otherwise smooth interior surface. About60-80 coarse fibers are present in each inter ­node . Though essentially transverse, they are

190

FIG. 2. Galatbealinum mexicanum Adegoke sp.nov. Paratype, UCM P 12155. Anterior region of para­type showing well-defined segments, coarse transversefibers, and some encrust ing calcareous annelid tubes,X 1.7.

rather irregularly oriented, and a few are evenconfluent. The interior wall is a glossy, dark­brown color, and is devoid of the feltlike layer.Both the extreme anterior and posterior ends ofthe tubes are unknown.

DIMENSIONS: Holotype: length 147.5 mm, di­ameter of wider anterior end 2.5 mm, diameterof smaller posterior end 2.2 mm, average lengthof segments 4.0 mm, th ickness of wall 0.1 mm,thickness of coarse fibers 15-22f-l. Paratype:length 77.5 mm, diameter of wider anterior end2.4 mm, diameter of posterior end 1.96 mm,average length of segments 4.5 mm, thicknessof wall about 0.1 mm, thickness of coarse fibers15-22f-l.

HOLOTYPE: Univ . Calif. Mus. Paleo, no.32882 , locality B-7469.

PARATYPE : UCMP no. 12155, from type local­ity.

PACIFIC SCIENCE, Vol. XXI, April 1967

FIG. 3. Galaibealinum mexican11m Adegoke sp.nov. Anterior end of holotype showi ng a few seg­ments wi th coarse fibers and remna nts of segmenta lfrills at the nodes, X 5.

FIG. 4. Galatbcalinum mexicanum Adegoke sp .nov. Part of holotype enlarged to show irr egul arcoarse fibers, X 5.

OCCURRE N CE : UCM P locality B-7469 . Fewtubes and some echinoids dredged by the Ver­million Sea Expedition S.I.O., from the Gulfof Tehuantepec, Mexico. Latitude 14°28'N to14° 29'N . Longitude 93° 09'W to 93° 10'W.Depth 1,935-1 ,974 fathoms. Field no. P-128­58.

REM ARKS: Galatbealinum mexicanum sp.nov. resembles other described species of Gala­tb ealinran in the possession of a dark-brown ,segmented tube covered externally by a thin , fri ­able, feltlike layer. Its dimensions are closest to

Pogonophora from Tehuantepec-c-Anscoxn

FIG. 5. Galathealinum mexicanum Adegoke sp.nov. Part of paratype enlarged to show coarse fibersand details of constricted segmental junctions, X 5.

FIG. 6. Galathealinum mexicanum Adegoke sp.nov. Part of paratype enlarged to show three encrust­ing annelid tubes, X 5.

191

FIG. 7. Galathealinum mexicanum Adegoke sp.nov. Part of paratype enlarged to show details ofsegmental junction and remnants of segmental frillsat nodes.

those of G. bracbiosum Ivanov, whose diameterranges from 2.0 to 2.6 mm, from which it maybe readily distinguished by the longer segments(about 4.0 mm long as against 1 mm in G.bracbiosum; see Ivanov, 1963 : Fig. EI62).Moreover, the coarse fibers in the new speciesmeasure 15-22[!, whereas they are 7-12[! thickin G. bracbiosam.

From G. bruuni Kirkegaard , the new speciesmay be distinguished by its larger dimensions,relatively weaker segmental frills, and thicker,coarser fibers (2-4[.t thick in G. brunni),

The new species may be readily distinguishedfrom G. arcticum Southward by its larger diam­eter (1.33-1.95 mm in the latter); largerlength-diameter ratio of each segment, which is:about 2 in the new species and 1 in G. arcticum ;and the thicker coarse fibers, which are only1-2[! thick in G. arcticum .

The longest fragment represented in the col­lection is 147 .5 mm long. As the extreme ante­rior and posterior ends of this tube are not­represented , and because of the rather minorvariation in taper between the two ends (ante-­rior diameter 2.5 mm, posterior diameter 2.2:

192

rnm ) , it is here suggested that the total actuallength of the tube may be several times thelength of this fragment.

Segment al funn el-like frills, a common char­acteristic of the genus, are only weakly repre­sented here (Figs. 3, 7) . According to Ivanov( 1963:412) , these frills are soft and pl iant inG. bracbiosnm and consist entirely of the exter­nal fibrous layer. It is, therefore, easily conceiv­able that these frills, originally present on thisnew species, became shrunken and inconspic­uous because of the poor conditions of preserva­tion of the tubes. Th e marked concentration ofirregularly oriented coarse fibers in the vicinityof each segmental junction (see Figs. 3, 4 ) sup­ports this contention.

Pogonophoran tubes are generally straight.Most of the tubes of this species in the collec­tion studied are also straight (see Fig. 2). Afew, however, are curved (see holotype, Fig.1) . This curvature is considered to be a shr ink­age phenomenon, as a result of drying.

REFERENCES

CUTLER, E. B. 1965. Pogonophora from theeastern tropical Pacific, including two newspecies of Siboglinsm. Pacif. Sci. 19 (4):422-426, 13 figs.

PACIFIC SCIENCE, Vol. XXI, April 1967

HARTMAN, O. 1961. N ew Pogonophora fromthe eastern ,P acific Ocean. Pacif. Sci. 15 (4 ) :542-546.

- - - and ]. L. BARNARD. 1960. The benthicfauna of the deep basins off southern Cali­forn ia. Allan Hancock Pacif. Exped. 22 :217­284.

IVANOV, A. V. 1961. New pogonophores fromthe eastern part of the Pacific Ocean. I. Gala­tbeallnum bracbiosum sp. n. Zool. Zh. 40 :1378-1384.

--- 1962. Ne w pogonophores from theeastern part of the Pacific Ocean. II . H epta­brachia ctenophore sp. n., and H . canadensissp. n. ZooI. Zh . 41:893-900.

- -- 1963. Pogonophora . ( Translated andedited by D. B. Carlisle.) Consultants Bureau,N ew York. 479 pp.

KIRKEGAARD, J. B. 1956. Pogonophora, Gala­thealinum brueni n. gen., n. sp., a new repre­sentative of the class. Galathea Rept. 2, 79­83.

- - - 1956a. Pogonophora. First records fromthe eastern Pacific. Ibid. 2:18 3- 186.

--- 1961. Pogonophora. III. The genusLam ellisabella. Ibid. 4:7-10.

SOUTHWARD, E. C. 1962. A new species ofGalatbealinum (Pogonophora) from the Ca­nadian Arctic. Canadian J. Zool. 40:385-389.