FISHERY BULLETIN: VOL. 75, NO. 2 



For each taxon a synonymy, bibliographic refer- 

 ences (selected for the genera, and complete for 

 the species), location of type-specimens, descrip- 

 tions, and distributional data are given, as are 

 variations for some species. Detailed accounts of 

 the spermatophores (both as attached to the fe- 

 males and as they appear when removed from the 

 terminal ampullae of the males) of three species 

 are also presented. These are the only species for 

 which spermatophore-bearing females were 

 secured. 



Bate (1881) was the first to describe species of 

 the generic complex treated here, assigning all 

 except one — which was assigned to Solenocera 

 Lucas (1849) — in a new genus, Haliporus. A year 

 later, Smith (1882) proposed the genus Hymeno- 

 penaeus for another new species belonging to that 

 complex. Subsequently, Bate (1888) expanded his 

 preliminary descriptions of Haliporus and corre- 

 sponding species, and pointed out that the one he 

 had placed in Solenocera, together with two 

 others, should be relegated to a new genus, 

 Philonicus. After his manuscript was in press, he 

 discovered that the latter name was preoccupied 

 and changed it to Pleoticus in the Introduction. 

 Bouvier ( 1906b) presented a revision of the genus 

 Haliporus in which he recognized 19 species, most 

 of which had been described after Bate's last 

 contribution (1888). He separated them into three 

 groups on the basis of the relative length of the 

 posterior two pairs of pereopods, the relative 

 diameter of the proximal part of the respective 

 carpi, and the consistency of the integument. He 

 failed to recognize other important supraspecific 

 differences which led him to group together 

 species which are not closely related. Burkenroad 

 (1936) disagreed with Bouvier's arrangement 

 and, as a result of an extensive investigation, 

 recognized two genera, Haliporus and Hymeno- 

 penaeus. Several other generic names have been 

 proposed and later synonymized with Hymeno- 

 penaeus, a clear indication of the taxonomic diffi- 

 culties presented by this complex. 



The genus Hymenopenaeus was defined by 

 Burkenroad (1936) as those "Solenocerinae with- 

 out podobranchs behind VIII; with well-developed 

 prosartema and only a single pair of lateral telson 

 spines in adult stages, and with cylindrical 

 filiform antennular flagella." Within it, he recog- 

 nized four separate groups based on the presence 

 or absence of branchiostegal or pterygostomian 

 spines and the arrangement of the epigastric and 

 rostral teeth. 



An examination of Atlantic, eastern Pacific, 

 and Hawaiian species, supplemented by material 

 from the Indo-West Pacific region, convinces me 

 that, in addition to the arrangement of the mid- 

 dorsal teeth on the carapace, the following charac- 

 ters are more reliable than the branchiostegal and 

 pterygostomian spines in ascertaining inter- 

 relationships of the species previously included in 

 Hymenopenaeus: shape of the antennular flagella 

 and rostrum, proportions of the carapace, number 

 and comparative size of the articles of the man- 

 dibular palp, presence or absence of certain 

 carinae on the carapace, relative dimensions of 

 the posterior two pairs of pereopods, location of the 

 distolateral spine (terminal or subterminal) of the 

 lateral ramus of the uropod, structure of the 

 petasma, and degree of development of the arthro- 

 branchia on somite VII. 



A comparative study based on the characters 

 cited above indicates that the species under con- 

 sideration should be assigned to five genera: 

 Hymenopenaeus , Pleoticus, and Haliporoides — 

 which had been erected previously — and Hadro- 

 penaeus and Mesopenaeus — which are proposed 

 here. 



Diagnoses of the four groups established by 

 Burkenroad (1936) within Hymenopenaeus to- 

 gether with the conclusions resulting from my 

 revision of this species-complex follow. 



Group I. This division contained the western 

 Atlantic H. muelleri and H. tropicalis, and the 

 Indo-West Pacific (Red Sea) H. steindachneri. As 

 pointed out by Burkenroad, these species share 

 the arrangement of the epigastric and rostral 

 teeth, which are separated by regularly decreas- 

 ing intervals anteriorly, and the absence of 

 branchiostegal and pterygostomian spines; to 

 these characters may be added the presence of 

 orbital spines and the lack of distinct branchio- 

 cardiac carinae. Several different features occur 

 in tropicalis which I consider to be of sufficient 

 importance to justify a separate genus, for which 

 I propose the name Mesopenaeus. Moreover, the 

 western Atlantic robustus, which was placed in 

 Group II by Burkenroad, shares basic characters 

 with muelleri and steindachneri; consequently, 

 the three are grouped herein under the available 

 generic name Pleoticus Bate (1888). 



Group II. The species assigned to this group 

 were characterized by possessing branchiostegal 

 but lacking pterygostomian spines and, like those 

 of Group I, exhibit epigastric and rostral teeth 

 separated by regularly decreasing intervals. 



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