PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF'V^SH'INGTON 113(4):1064-1078. 2000. Brachycalanus flemingeri and B. brodskyi, two new copepods (Crustacea: Calanoida: Phaennidae) from benthopelagic waters of the tropical Pacific Frank D. Ferrari and E. L. Markhaseva (PDF) Department of Invertebrate Zoology, National Museum of Natural History; Smithsonian Institution; Washington, DC. 20560-0534, U.S.A.; (ELM) Russian Academy of Sciences, Zoological Institute; Universitetskaya nab. 1, 199034, St. Petersburg, Russia Abstract.—Brachycalanus flemingeri, new species, has three setae on coxal endite of maxilla 1, a bifurcate worm-like sensory seta on the exopod of max- illa 2, a distal, semicircular protrusion posteriorly on the basis of swimming leg 1, and lacks a medial seta on coxa of switnming leg 4. Brachycalanus brodskyi, new species, is differentiated by its large size, 4.0 mm, and a semi- circular row of small denticles distally and posteriorly on the basis of swim- ming leg 1. Brachycalanus ordinarius (Grice, 1972) is redescribed and sepa- rated from the remaining species by the exopod of maxilla 2 with a distally constricted worm-like seta with a small lobe near the point of constriction. All three species have nine sensory setae on the distal basal lobe plus exopod of maxilla 2; this number of sensory setae has been reported for one other phaen- nid copepod and several scolecitrichids. Suggested shared derived character states for the species oi Brachycalanus Farran, 1905 are epicuticular extensions of the female genital complex and the following two abdominal somites, and knife-like aesthetascs on female antenna 1. The genus Brachycalanus Farran, 1905 m (Grice 1972). No adult males of a species includes four species: B. atlanticus (Wol- of Brachycalanus have been collected. The fenden, 1904), B. bjornbergae Campaner, two new Brachycalanus species described 1978; B. ordinarius (Grice, 1972) and B. here are the first records of the genus from rothlisbergi Othman & Greenwood, 1988 the eastern tropical Pacific Ocean. Brachy- although Othman & Greenwood (1988) calanus ordinarius is redescribed, based a suggested that specimens of B. atlanticus paratype. reported by Farran (1905) do not belong to the same species as the specimens of Wol- Materials and Methods fenden (1904). Different species have been reported from the North Atlantic Ocean The specimens from Hawaii collected on (Wolfenden 1904, Farran 1905, Grice 6 July 1997 may have been in a plankton 1972), the South Atlantic Ocean (Campaner net for up to 12 hours prior to sample fix- 1978) and the Gulf of Carpentaria in the ation with 4% formaldehyde; few internal western tropical Pacific Ocean (Othman & tissues remain in these specimens. The Greenwood 1988); only B. atlanticus has specimen collected from Volcano 7 during been reported more than once, by Wolfen- November 1988 was fixed at its depth of den (1904) and Farran (1905). Specimens capture with gluteraldehyde; most internal of Brachycalanus usually are collected tissues remain. Ferrari & Markhaseva from near-bottom localities at depths from (1996, 2000), give further details about col- 72-100 m (Campaner 1978) to 992-1000 lections from Volcano 7 and Hawaii. In the VOLUME 113, NUMBER 4 1065 laboratory, specimens from both localities toward the distal end of an appendage are were preserved in 0.5% propylene phen- distally polarized; an array arranged in a oxytol/4.5% propylene glycol/95.0% deion- semicircle are radially polarized. Specimens ized freshwater. During examination, spec- remain deposited in the National Museum imens were cleared in steps through 50% of Natural History, Smithsonian Institution, lactic acid/50% deionized freshwater to Washington, D.C. (USNM). 100% lactic acid, stained by adding a so- lution of chlorazol black E dissolved in Brachycalanus flemingeri new species 70% ethanol/30% deionized freshwater, and Figs. 1-3 examined with bright-field and with differ- ential interference optics. Drawings were Specimens.—\\o\oXyY>e^ (USNM 307711) a made with a camera lucida. Dissected and dissected 2.41 nmi female; prosome 2.02 undissected specimens are preserved in mm, urosome 0.44. Paratypes: (USNM 70% ethanol/30% deionized freshwater. 307712) 4 mature females (2.01; 2.04, two Cephalic appendages are abbreviated Al specimens; 2.37 mm) and 3 males CV (2.01; = antenna 1; A2 = antenna 2; Mn = man- 2.07; 2.07 mm) and 1 CIV female (1.65 dible; Mxl = maxilla 1; Mx2 = maxilla 2. mm). Type locality: eastern tropical Pacific Thoracic somites are Thl-7. Appendages Ocean, 19°43'27.01"N, 156°04'35.46"W, off on thoracic somites are Mxp = maxilliped Kona, Island of Hawaii, 6 Jul 1997. (thoracopod 1); PI-5 = swimming legs 1- CVI Female.—(Fig. lA) Cephalon and 5 (thoracopods 2-6). The caudal ramus is Thl fused; Th2-Th4 separate; Th5 and Th6 CR. Measurements are lengths; the length separated but not well articulated. Laterally, of the whole animal is measured from the posterior comers of prosome triangular; anterior edge of the cephalothorax to the dorsally, acutely triangular and almost posterior edge of the caudal ramus, and reaching mid-length of genital complex does not include the overlap onto the gen- (Fig. IG). Th4 with 2 sensilla laterally; ven- ital complex of the posterior edge of the sixth thoracic somite. Designations of ap- tral longer; Th5 with 1 short dorsal sensilla pendage segments follow Ferrari (1995), laterally. Genital complex and following 2 Ferrari & Dahms (1998) and Ferrari & abdominal somites (Fig. ID, E, H) with Markhaseva (2000). The coxa of the max- small, scale-like spinules. Genital complex illiped of copepods has one lobe with a symmetrical. group of setae (Ferrari & Ambler 1992, Rostrum (Fig. IB, C): subdivided plate Martinez Arbizu 1997); the remaining three with 2 filaments. groups of setae on the calanoid syncoxa be- Al: reaching Th3 and of 24 articulating long to the praecoxa. Articulating arma- segments with groups of setae: 3?, 7?, 3?, ment elements of appendages are termed 2?, 3?, 2?, 3?, 5?, 1, 1, 3?, 1, 3?, 1, 2?, 1, setae regardless of their morphology or de- 2?, 2?, 1, 1, 2?, 2?, 2?, 5-1-1. gree of rigidity. Two setae and one aesthe- A2 (Fig. 2A): coxa with 1 seta and den- tasc on a segment of antenna 1 are desig- ticles. Basis with 2 setae. Ri 2-segmented nated 2-1-1; "?" indicates that a setal ele- with 2 and 14 (6 terminal and 8 subtermi- ment was broken so that its identity on an- nal) setae. Re 7 articulated segments with tenna 1 could not be determined and only 0, 1, 1, 1, 1, 1, and H-3 setae; 2nd segment the scar at the location of attachment of the with several small indentations on medial seta was counted. Setules are epicuticular face and seta minute. extensions of a seta; denticles are epicutic- Mn: coxal gnathobase (Fig. 2C) some- ular extensions of an appendage segment; what elongate with 3 compound and 4 sim- spinules are epicuticular extensions of a so- ple teeth and 1 .seta. Basis with 3 setae (Fig. mite. An array of denticles whose tips point 2B). Re indistinctly segmented apparently 1066 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON Fig. 1. Brachycalanus flemmaeri new species. A, habitus, right lateral; B, anterior part of cephalon, ventral; C, rostrum, anterior-ventral; D, Th5-6 and urosome, right lateral; E, urosome, ventral; F. genital complex, ventral; G, posterior Th4, Th5-6 and genital complex, dorsal; H, urosome dorsal. Scale lines are 0.1 mm. VOLUME 113, NUMBER 4 1067 with 1, 1, 1, 1, 2 terminal setae; Ri 2-seg- P2 (Fig. 3C, D): all segments anteriorly mented with 2 and 9 setae. and posteriorly with complex arrays of Mxl: praecoxa elongate with 9 terminal, large and small denticles; arrays may be 1 anterior and 4 posterior setae (Fig. 2E); distally or radially polarized. Coxa with coxal epipodite with 1 thin, short seta and medial seta. Basis without seta. Re 3-seg- 8 long, thick setae; coxal endite with 3 se- mented, proximal with 1 medial and 1 lat- tae; 1st and 2nd basal endites with 4 and 5 eral seta, middle with 1 medial and 1 lateral setae respectively (Fig. 2D). Ri with 11 se- seta, distal with 4 medial, 1 terminal, 3 lat- tae (3-1-3+5); Re with 10 setae. eral setae. Ri 2-segmented, proximal with 1 Mx2 (Fig. 2G): proximal praecoxal en- medial seta, distal with 2 medial, 2 termi- dite with 5 setae; distal with 3 setae, 1 poor- nal, 1 lateral setae. ly sclerotized. Proximal coxal endite with 1 P3 (Fig. 3E, F): all segments anteriorly short, poorly sclerotized sensory seta and 2 and posteriorly with complex arrays of long well-.sclerotized setae; distal coxal en- large and small denticles; arrays may be dite with 1 thick and 2 thin setae. Proximal distally or radially polarized. Coxa with basal endite with 1 long, thick seta, 1 long, medial seta. Basis without seta. Re 3-seg- thin seta and 2 poorly sclerotized sensory mented, proximal with 1 medial and 1 lat- setae. Distal basal lobe + Re with 9 sensory eral seta, middle \)Pith 1 medial and 1 lateral setae; 7 brush-like setae with short setules seta, distal with 4 medial, 1 terminal, 3 lat- and 2 worm-like setae, 1 of which is bifur- eral setae. Ri 3-segmented, proximal with 1 cate toward its distal end. medial seta, middle with 1 medial seta, dis- Mxp (Fig. 2F): syncoxa with 1 worm- tal with 2 medial, 2 terminal, 1 lateral setae. like seta on proximal lobe; 1 sclerotized and P4 (Fig. 3G-I): all segments except prox- 1 worm-like sensory seta on middle lobe; 1 imal endopodal anteriorly and posteriorly sclerotized and 1 brush-like sensory seta with complex arrays of large and small den- with short setules on distal lobe; coxal lobe ticles; arrays may be distally or radially po- with 3 setae and distal denticles.