New species of Lucicutia and taxonomic status of L. grandis (Copepoda, Calanoida, Lucicutiidae)

Calanoid copepod specimens attributable to Lucicutia grandis (Giesbrecht, 1895), L. bradyana Cleve, 1904, L. wolfendeni Sewell, 1932, and L. rara Hulsemann, 1966) were studied from antarctic and subantarctic waters collected during RV Eltanin crusies 4–11 and 23, and RV Ob cruises 1 and 3. In addition, identified specimens from the Pacific and Indian Oceans deposited in the systematic collections of the National Museum of Natural History, Smithsonian Institution (Washington, DC, USA) and the Zoological Institute, Russian Academy of Sciences (St Petersburg) were also examined. Both sexes of a new species are described from the eastern tropical Pacific Ocean, L. hulsemannae. Lucicutia hulsemannae is distinguished from L. grandis, L. bradyana and L. wolfendeni by the morphology of the rostrum, genital complex, including plug, and leg 5 of both sexes. Lucicutia bradyana is not found outside the Southern Hemisphere but L. grandis is recorded from the Arabian Sea, the Bay of Bengal, tropical Indian Ocean, as well as its type locality in the eastern tropical Pacific Ocean. Lucicutia wolfendeni is found in all oceans except the Arctic Ocean. The status of L. bradyana, previously rejected as a separate species by Hulsemann (1966), is restored. Lucitutia rara is considered a junior synonym of L. bradyana.


Introduction
The genus Lucicutia includes 44 nominal species (Hulsemann 1966;Razouls 1995;Bradford-Grieve 1999). Despite a recent taxonomic revision of Lucicutia (Hulsemann 1966), identification of specimens attributable to species like L. grandis (Giesbrecht, 1895), L. wolfendeni L. bradyana Cleve, 1904 remained problematical. For example, in recent studies of calanoid copepods collected in the oxygen minimum zones of the Arabian Sea and the eastern tropical Pacific Ocean, L. grandis was reported to have similar ecology and feeding activity from both regions Wishner et al. 2000), while differing in morphology Wishner et al. 2000). The present taxonomic study shows clear morphological differences between the eastern tropical Pacific Ocean specimens of L. grandis and those from the Arabian Sea associated with the oxygen minimum zone. Specimens from the Female Total length 4.7-4.9 mm. Prosome 1.7-1.8 times longer than urosome. Cephalosome with pointed protrusions ( Figure 1A-C). Rostrum not divergent; rami closely spaced ( Figure 1D). Genital double-somite with conical plug ( Figure 1G, I, J). Anal somite nearly as long as two preceding somites together , with dorsal side strongly swollen ( Figure 1G-J). Caudal rami in dorsal view 1.0-1.3 times longer than anal somite and about five times longer than wide ( Figure 1E, F). Antennule exceeding body length by distal segment. Medial seta at exopodal segment 2 of P5 attenuate, thin at tip ( Figure 1K).

Remarks
The following combination of characters distinguishes the females of L. grandis from L. bradyana: anal somite swollen dorsally in lateral view (swollen ventrally in L. bradyana;  Figure 4D-F); genital-double somite with conical plug (rounded in L. bradyana; Figure  4D-F); medial seta at the exopodal segment 2 of female P5 attenuate and thin at the tip (in L. bradyana this seta robust; Figure 4G-I); rostral rami closely spaced (divergent in L. bradyana; Figure 4A-C). Lucicutia grandis differs from L. wolfendeni as follows: large anal somite swollen dorsally (anal somite of L. wolfendeni only slightly swollen dorsally; Figure  8D-F); genital double-somite of L. grandis with a conical plug (L. wolfendeni with an elongate-oval plug; Figure 8D-F); caudal rami of L. grandis are 1.0-1.3 times longer than anal somite (2.9-3.1 times longer than anal somite of L. wolfendeni; Figure 8C, D); rostral rami of L. wolfendeni are divergent ( Figure 8G-I) and not closely spaced as in L. grandis. Females of L. grandis are smaller than L. wolfendeni and L. bradyana. Total length of L. grandis females studied here is 4.7-4.9 mm; published records of females: 5.54 mm after ; 4.4-6.5 mm after Hulsemann (1966); and 3.8-4.0 mm after Ali-Khan and Ali-Khan (1982). However, larger sizes given by Hulsemann (1966) are for specimens identified here as L. bradyana (see below).
The left P5 basipod of males of L. grandis which is not elongate medially-distally ( Figure  2F, G) differs from both L. bradyana, in which there is an elongate medial-distal projection with varying number of terminal teeth (Figures 6B, D, 7A 2 -C 2 ), and L. wolfendeni in which the projection is present but less pronounced ( Figure 9F). The third exopodal segment of the left P5 of L. grandis is oval-rounded, while for L. bradyana it is elongate-oval and for L. wolfendeni it is elongate-triangular (Figures 2F, G, 6B, D, 7A 2 -C 2 , 9F). The second endopodal segment of the right P5 of L. grandis is unarmed ( Figure 2I, K), while that of L. bradyana is densely hirsute. The inner margin of the right basipod of L. grandis has a small tooth-like indentation which differs from the distinct, proximal-facing lobe of L. wolfendeni ( Figure 9G). Sizes of males of L. grandis here are smaller than the male studied by Giesbrecht (1895), 6.0 mm, and larger than those of Ali-Khan and Ali-Khan (1982), 3.0-3.6 mm, but similar to those recorded by , 3.9-4.60 mm, and Hulsemann (1966), 3.9-4.9 mm.
Lucicutia grandis was described originally by Giesbrecht (1895) from a single damaged male from the Eastern Tropical Pacific (1uN, 83uW); only the P5 was illustrated. Because   the description of species is based on an incompletely illustrated male, the identification of L. grandis has remained problematical. In a revision of the genus, Hulsemann (1966, p 719) mentioned ''None of the many subsequent records of Lucicutia grandis seems to be this species. Sewell (1932, p 289) proposed to establish for these records a new species, L. wolfendeni''. In the same publication several nominal species of Lucicutia were placed in synonymy with L. grandis, including L. bradyana Cleve, 1904. That is a decision we reconsider here. Lucicutia bradyana Cleve, 1904 is recognized as a separate species based on the differences between the two groups of specimens enumerated above. However, we accept Hulsemann's conclusion that L. challengeri Sewell, 1932 is a junior synonym of L. grandis. Sewell (1932, Text-Figure 95h, j) illustrates the female P5 with a thin medial seta on the second exopodal segment and the shape of male P5 typical for L. grandis observed here.

Distribution
Lucicutia grandis is found in the eastern tropical Pacific Ocean at 1uN, 839W (Giesbrecht 1895) and in the Indian Ocean north from 10u079S. Specimens identified as L. grandis by Hulsemann (1966, p 717) from Anton Bruun stations 134, 348A, 349B, 353A, 354A, and 355C are L. bradyana. However, specimens from stations 108, 112, 330, 332, and 342 (see Figure 2K) are L. grandis (Hulsemann 1966, p 717). Specimens from Discovery cruise III station 5251, Anton Bruun station 328 and John Murray Expedition station 76 were not reexamined here. Based on records from the existing literature Hulsemann 1966;Ali-Khan and Ali-Khan 1982) and data here, L. grandis is distributed in the northern part of the Indian Ocean, in the Arabian Sea and in the Bay of Bengal. The southernmost finding is 10u079S (Hulsemann 1966); the northernmost is 24u099, 64u279N (Ali-Khan and Ali-Khan 1982). Records from the Atlantic Ocean are ambiguous and date from Wolfenden (1911). However, Wolfenden's Figure 60 for L. grandis appears to be an illustration of L. bradyana. Bjö rnberg (1973, p 343) recorded L. grandis from the southeastern Pacific Ocean between 07uS and 58uS without providing descriptions or illustrations.

Female
Total length 5.5-6.1 mm. Prosome 1.45-1.60 longer than urosome. Cephalosome with slightly angular or rounded protrusions ( Figure 3A-C). Rostral rami divergent and widely spaced ( Figure 4A-C). Genital double-somite with rounded plug (Figure 4D-F). Anal somite nearly as long as, or slightly longer than two preceding somites together ( Figure 3A, B, D), with ventral side significantly swollen ( Figure 4D-F). Caudal rami in dorsal view 1.25-1.50 times longer than anal somite ( Figure 3A, B, D) and about 5.8-6.6 times longer   Male Total length 5.1-5.2 mm. Prosome 1.28-1.30 times longer than urosome. In some specimens urosome somites distinctively hirsute ( Figure 5A). Cephalosome with triangular or rounded protrusions ( Figure 5A, B). Rostrum of moderately divergent, nearly parallel rami ( Figure 5C). Caudal rami 6.2 times longer than wide. Antennule of 21 articulated segments reaching about the middle length of caudal rami, an indication of a subdivision is visible in segment 18 ( Figure 5E, F). Length of exopodal segment 1 of right P5 shorter than second. Surface of endopodal segment 2 hirsute. Basipod with knob at mid-length of medial margin; shape of knob variable (Figures 6A, C, 7A 1 -C 1 ). Shape of exopodal segment 3 of left P5 elongate, oval-triangular; medial distal part of basipod with elongate projection with variable number of teeth at the tip ( Figures 6B, D, 7A 2 -C 2 ).

Remarks
Total length of the type specimen is 5.7 mm (Cleve 1904); largest recorded size of a female is 6.2 mm (Wolfenden 1911, as Lucicutia maxima); smallest 5.0-6.15 mm (Bradford-Grieve 1999, as Lucicutia grandis). Total length published for males: 5.2 mm (Cleve 1904); 4.7-5.45 mm (Bradford-Grieve 1999, as Lucicutia grandis). The characters distinguishing L. bradyana from L. grandis are given above in the remarks for L. grandis. Hulsemann placed L. bradyana in synonymy with L. grandis but mentioned that it ''is doubtfully included in this synonymy'', and ''L. bradyana Cleve which is doubtfully referred to L. grandis in this paper…'' (Hulsemann 1966, p 717, 721, 736). In the present study, significant variability in P5 structure of males suggests those doubts were justified. Shape of the left and right basipod of male P5 distinguishes L. bradyana from L. grandis, but those shapes vary within a species. Among specimens of L. bradyana studied here is a male whose P5 ( Figure 7A 2 ) is similar to that illustrated by Cleve (1904, Figure 34) in the original description of L. bradyana. Despite this variability, the left basipod of all specimens of L. bradyana has an elongate projection medially with teeth on the tip; right basipod has a distinct knob at mid-length. The medial distal edge of the basipod of the left P5 of L. grandis has a saw-like, toothed margin; the medial edge of the basipod of the right P5 has a small bump.
Lucicutia rara was described from the male gender only, and its similarity to L. bradyana noted (Hulsemann 1966, p 735-736, Figures 45, 46, 103). The holotype of L. rara (NMNH 113545) and two males identified as L. rara by Hulsemann from Anton Bruun station 355C were re-examined ( Figure 6C, D) and compared with L. bradyana. That comparison shows that these specimens are conspecific.

Distribution
The type locality of L. bradyana Cleve, 1904 is east of South Africa in the Agulhas Current. The species is recorded from the South Atlantic Ocean between 10uS and about 35uS (as L. maxima) by Wolfenden (1911); from the south-western Pacific Ocean (as L. grandis) by Bradford-Grieve (1999), and now from the Indian Ocean between 19uS and 40uS
Lucicutia hulsemannae sp. nov.  Material examined Female Total length 6.25-6.30 mm. Prosome 1.67-1.80 times longer than urosome. Cephalosome with a pair of low triangular protrusions ( Figure 10A). Rostral rami divergent from a swollen base ( Figure 10D). Genital complex symmetrical with irregular, conical plug ( Figure 10C). Second urosome somite 1.37 times wider than urosome somite 3 in dorsal view and 1.31 times wider than urosome somite 3 in lateral view. Third urosome somite longer than adjacent somites: 1.1-1.2 times longer than urosome somite 2 and 1.2-1.4 times longer than anal somite. Anal somite not swollen dorsally ( Figure 10C). Caudal rami in dorsal view nearly three times longer than anal somite and 5.5 times longer than wide ( Figure 10A). Antennule reaching the end of caudal rami. P1 with large pore on basipod; inner seta of basipod originating on the outer, posterior wall of pore ( Figure 10E); both states shared among species of the family. P5 with threesegmented rami. Medial seta on exopodal segment 2 of P5 attenuate and thin toward its tip ( Figure 10F).

Male
Total length 5.80-6.00 mm. Prosome 1.44-1.55 longer than urosome. Cephalosome laterally with pointed protrusions ( Figure 11A, B). Rostrum with rami nearly parallel ( Figure 11E). Caudal rami 5.8 times longer than wide. Antennule of 21 articulated segments, 18th the longest ( Figure 11F-H). Right P5 with exopodal segment 1 shorter than 2 and with a thin sclerotized lamella at mid-length; exopodal segment 2 with broad medial hirsute lobe. Basipod of right P5 basipod variable in shape, usually with knob along medial margin ( Figure 12A, B). Third exopodal segment of left P5 elongate, ovalrectangular; basipod with a medial projection pointed distally, with varying number of teeth at tip ( Figure 12A, C). were found south of 56uS; they are identified here as Lucicutia cf. intermedia. Lucicutia intermedia occurs north of 22uS. Because species of the genus usually exhibit great variability, a series of specimens is needed to determine this variability before the presence of L. intermedia in antarctic waters can be verified. Lucicutia bradyana is quite common in the samples and is a new record and the sixth species of lucicutiid recorded from antarctic waters. All species of Lucicutia recorded in antarctic waters show broad distributions throughout the oceans of the world (Hulsemann 1966). Our results demonstrate the absence of a specific lucicutiid fauna in antarctic waters.