Diagnosis_Genus: Hyporthodus Gill. The cheeks and opercula, as well as the supramaxillary bones, are covered with scales. The lower jaw is naked. The preoperculum has at its angle a strong spine, which is itself more or less dentated ; its ascending margin is vertical and quite strongly serrated; its horizontal inferior margin has also several more distant teeth. The operculum is armed with three spines. The number of rays is indicated in the following formula : D. XL. 14. A. III. 10. P. 17. V. I. 5. The color of the body may be described as tawny, minutely punctulated with brown or black, which so prevail on the caudal peduncle, the dorsal, anal and ventral fins, that those parts are quite black. There are on each side four narrow lighter bands, along each of which are also about three light blue spots. The caudal and pectoral fins are yellowish. The articulated portions of the dorsal and anal exterior to a line continuous with the margin of the spinous portions are lighter, and also assume a yellowish hue. The first transverse line extends from the fifth or sixth spines of the dorsal to the axilla of the pectoral fin; the second from the eighth dorsal spine ; the third from the eleventh ; the fourth from about the fifth articulated ray. The species, on account of its coloration, resembles the Hypoplectrus chlorurus Gill, (Plectropoma chlorurum Cuv. et Val.,) as much as any other, but is generically distinct, and a true Serranus Cuv. Two specimens were obtained at Newport, Rhode Island, by Messrs. N. and E. Smith. Both specimens are young, the length being less than two inches.

Diagnosis_Species: Serranus niveatus Cuvier & Valenciennes. (Le Mérou neigé). It is in the seas of Brazil that this new species of serrau is caught; M delalande has reported it to us, and we find no description of it in the authors we have consulted. Its forms are similar to those of the other groupers which we have already described. The body is short; the serrations of the preopercle are deeply marked, and the lower spine of the operculum is very small. The odd fins are largely scaly: they are rounded. On a brown background, all the fish is covered with sparse pure spots. It is from this character that we have taken the name which will designate now this new species.

Other description (Mexican-fish): The Snowy Groupers have robust compressed oval bodies that are deepest at the origin of their dorsal fin. Adults are dark brown and the edge of their spiny dorsal fin is black. Juveniles are dark brown with prominent white spots in vertical rows on the rear of their head and body extending onto the dorsal fin; these spots fade quickly upon death. Their caudal and pectoral fins are transparent with a yellowish tinge. They have a black saddle on their upper caudal fin base that reaches the lateral line. They have a large terminal mouth equipped with depressed teeth on the sides and roof of the mouth. Their anal fin has three spines and nine rays; their caudal fin is rounded in juveniles and straight to concave in adults; their dorsal fin has 11 spines, with the third or the fourth being the longest, and 13 to 15 rays; and their pectoral fins are behind their pelvic fins. In juveniles the pelvic fins are longer than the pectoral fins. They have 22 to 26 gill rakers and are covered with rough scales.

Body_adult_max_length: 120 cm (IUCN)
Body_adult_common_length: 60 cm (Fishbase)
Body_sexual_maturity_female_length: 450-500 mm TL (Kowal, 2010)
Weight_adult_max: 30 kg (IUCN)
Sequence_16S: AF297310 (Craig & Hasting, 2007)
Sequence_12S: AY949343 (Craig & Hasting, 2007)
Sequence_TMO4C4: AY949262 (Craig & Hasting, 2007)
Sequence_H III: AY949535 (Craig & Hasting, 2007)
Stage_duration_egg_hatching: 1-5 days (Kowal, 2010)