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NO. 1 GARTH AND STEPHENSON : PORTUNIDAE 61
Carapace hexagonal, only moderately broad, fairly convex, and bearing the following ridges: mesogastrics, metagastrics, and epibranchials
(plus others different in the two species) ; postlateral corner smoothly
rounded. Front four-toothed (considering process lateral to the four
teeth as inner subdivision of inner supraorbital angle), teeth of approximately equal size, deeply separated from inner supraorbital angles. Orbital region with inner supraorbital angles clearly subdivided into a narrower, sharper inner lobe and a broader, blunter outer lobe; two supraorbital fissures, and a deep suborbital fissure with a distinct lateral
tooth; main suborbital tooth well developed. Anterolateral teeth: first
live teeth alternately large and small. Third maxillipeds with a slight
production of the anteroexternal angle of the merus. Chelipeds massive;
anterior border of arm with massive spines; wrist with inner spine strong
and three spines or spinules on outer surface; hand with six distinct
costae, inner costa of upper surface bearing two stout spines. Fifth leg
with posterior border of merus bearing a stout spine; posterior border
of propodus minutely serrated. Male abdomen with ultimate segment
triangular, tip rounded.
The following are their differences (those marked with an asterisk
apply to some species of Charybdis other than C. erythrodactyla also) :
Carapace with protogastric ridge replaced in Cronius ruber with
diffusely granular areas; a broad gap between metagastric and epibran-
chial ridges; faint cardiac and (single) mesobranchial ridges sometimes
detectable*. Basal antennal article bearing spine, not touching front,
therefore not excluding flagellum from orbit*. Anterolateral teeth nine,
not seven; in the young, five recognizable. Chelipeds with all main carinae of hand strongly granular, not smooth; under surface of hand with
squamiform markings; four spines, not five, on upper surface of hand*.
Male abdomen with penultimate segment with gradually converging
sides, not with proximal half nearly parallel-sided. Male first pleopod
smoothly curved, not sinuous, and lacking subterminal tip.
Of the above differences, the only feature that would serve for generic separation of Cronius from Charybdis is the number of anterolateral teeth in the adult. As indicated by Stephenson and Campbell
(1959), the genus Charybdis occupies a critical position in evolutionary development from portunids possessing five anterolateral teeth (e. g.,
Thalamita) to those with nine (e. g., Portunus). Cronius has advanced
from Charybdis, with 6 or 7 teeth, by the addition of further antero-
Object Description
Description
| Title | AHF-PUB-MMB-01~065 |
| Format (imt) | image/tiff |
| Contributing entity | University of Southern California |
| Filename | AHF-PUB-MMB-01~065.tiff |
| Full text | NO. 1 GARTH AND STEPHENSON : PORTUNIDAE 61 Carapace hexagonal, only moderately broad, fairly convex, and bearing the following ridges: mesogastrics, metagastrics, and epibranchials (plus others different in the two species) ; postlateral corner smoothly rounded. Front four-toothed (considering process lateral to the four teeth as inner subdivision of inner supraorbital angle), teeth of approximately equal size, deeply separated from inner supraorbital angles. Orbital region with inner supraorbital angles clearly subdivided into a narrower, sharper inner lobe and a broader, blunter outer lobe; two supraorbital fissures, and a deep suborbital fissure with a distinct lateral tooth; main suborbital tooth well developed. Anterolateral teeth: first live teeth alternately large and small. Third maxillipeds with a slight production of the anteroexternal angle of the merus. Chelipeds massive; anterior border of arm with massive spines; wrist with inner spine strong and three spines or spinules on outer surface; hand with six distinct costae, inner costa of upper surface bearing two stout spines. Fifth leg with posterior border of merus bearing a stout spine; posterior border of propodus minutely serrated. Male abdomen with ultimate segment triangular, tip rounded. The following are their differences (those marked with an asterisk apply to some species of Charybdis other than C. erythrodactyla also) : Carapace with protogastric ridge replaced in Cronius ruber with diffusely granular areas; a broad gap between metagastric and epibran- chial ridges; faint cardiac and (single) mesobranchial ridges sometimes detectable*. Basal antennal article bearing spine, not touching front, therefore not excluding flagellum from orbit*. Anterolateral teeth nine, not seven; in the young, five recognizable. Chelipeds with all main carinae of hand strongly granular, not smooth; under surface of hand with squamiform markings; four spines, not five, on upper surface of hand*. Male abdomen with penultimate segment with gradually converging sides, not with proximal half nearly parallel-sided. Male first pleopod smoothly curved, not sinuous, and lacking subterminal tip. Of the above differences, the only feature that would serve for generic separation of Cronius from Charybdis is the number of anterolateral teeth in the adult. As indicated by Stephenson and Campbell (1959), the genus Charybdis occupies a critical position in evolutionary development from portunids possessing five anterolateral teeth (e. g., Thalamita) to those with nine (e. g., Portunus). Cronius has advanced from Charybdis, with 6 or 7 teeth, by the addition of further antero- |
| Archival file | hancockunpub_Volume20/AHF-PUB-MMB-01~065.tiff |
