GORE: LARVAL DEVELOPMENT OF GALATHEA ROSTRATA 



galatheid species known to occur in the western 

 Atlantic is unknown. 



The majority of our knowledge on galatheid lar- 

 vae comes from studies conducted on species from 

 the eastern Atlantic and Pacific Oceans, and as- 

 sociated seas such as the Red, Mediterranean, or 

 North Seas. Lebour ( 1930) first characterized lar- 

 vae in the family Galatheidae, and Gurney ( 1942) 

 was the first to provide a synopsis of larval fea- 

 tures based on Lebour's work and studies he made 

 on western Pacific galatheid larvae. As might be 

 expected, only some of the characters considered 

 important by Gurney in 1942 remain valid today, 

 and the lack of detailed descriptions in earlier 

 studies on galatheid larval morphology prevents 

 comparative statements to be made among most of 

 the species for which the larvae are known. 

 Nevertheless, morphological differences in ros- 

 tral, carapacial, antennal, abdominal, and tel- 

 sonal features continue to be of some value in 

 distinguishing the larvae of at least five galatheid 

 genera. 



In general, the larvae so far described for species 

 of Munida share several features with those 

 known from Galathea and Pleiironcodes, and are 

 thus somewhat indicative (as seems true for the 

 adults) of close relationships among the three gen- 

 era. Pleuroncodes, an eastern Pacific genus, is 

 morphologically very similar to Munida in several 

 larval features, more so than are larvae of 

 Galathea as presentlydescribed. As noted in the 

 following synopses, the larvae of the three genera 

 can be easily separated. The adults, based on pres- 

 ent taxonomic criteria, are distinct and generic 

 status is undoubtedly warranted. 



The genus Munidopsis, on the other hand, is a 

 heterogeneous grouping of forms, some adults 

 bearing little resemblance to others in the taxon 

 (see Mayo 1974, for discussion). The larvae from 

 the sole species so far described, however, are cer- 

 tainly distinctive and do not resemble those from 

 other genera. The genus Miinidopsis, as presently 

 constituted, would seem to provide an ample 

 example of a taxon wherein the relationships 

 among the various species (and perhaps their ele- 

 vation to generic status) might be clarified on the 

 basis of morphological relationships among their 

 larvae. 



The first zoeal larvae of the eastern Pacific 

 species Ceruimunida johni (Fagetti 1960) are 

 quite spinose but could perhaps be confused with 

 either Munida or Pleuroncodes larvae (Fagetti 

 and Campodonico 1971). It remains to be seen 



whether later larval stages would be more distinc- 

 tive. The presence of a single ventral antennal 

 spine (instead of two as seen in other genera) is of 

 limited value, because Galathea and Munida 

 exhibit a single spine in stage I and two spines in 

 later stages (see below). 



In the genus Galathea, larvae are principally 

 known from northeastern Atlantic species de- 

 scribed by Lebour (1930, 1931) and Sars (1889). 

 Live specimens of these species may be separated 

 from larvae of G. ro.strata by chromatophore color 

 and position, but unfortunately no further de- 

 tailed comparison is possible until the former 

 species are completely redescribed and illustrated. 

 This holds true for most of the studies by the 19th 

 and early 20th century authors which were listed 

 in Gurney (1942). The "Galathea sp." briefly de- 

 scribed and illustrated by Al-Kholy (1959) from 

 the Red Sea agrees in several respects with "typi- 

 cal" Galathea larvae, but differs in others. 

 Whether it may be equated with Gurney's (1938) 

 G. longimana remains uncertain as the brief de- 

 scriptions and illustrations of both authors pro- 

 hibit meaningful comparison between the two 

 studies, and those on other Galathea larvae. 



In order to facilitate comparison between the 

 two western Atlantic Galathea species a summary 

 of larval features exhibited by G. rostrata is pro- 

 vided in Table 2. These may be applied both to G. 

 agossizii, when its larvae become known, and to 

 other Galathea larvae when expanded or more 

 complete descriptions are provided. In addition, a 

 provisional synopsis of larval characters for the 

 five genera discussed above is also presented. The 

 summaries have been extracted from the more 

 reliable larval descriptions, as so noted, and may 

 allow distinction among the more typical larvae in 

 each genus. As our knowledge increases further 

 modification may be required. 



SYNOPSES OF GALATHEID LARVAE 



In the following section, emphasis is placed on 

 the setal-spinal formulae of the larval telson. 

 Conventionally, this formula may be expressed 

 thusly: 8+8, indicating that eight telsonal pro- 

 cesses, consisting of fixed and movable spines, 

 setae, and thin hairs, occur on each side of the 

 telsonal midline. It is apparent now that the type 

 of these processes may provide a useful reference 

 feature in distinguishing between the various 

 galatheid larvae. Accordingly, spines (whether 

 movable or fixed) are herewith denoted by Roman 



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