- The form varies from lumpy masses to fans. Surface covered with crowded, sharp monticules.
Boardman and Utgaard (1966):
- Zoaria generally are irregularly massive or frondose, less commonly are thin incrusting expansions. Zoaria commonly have subramose or ramose, less commonly subfrondose, protrusions. A large massive colony measures 10 cm wide, 13 cm long and 6 cm high; large fronds are at least 12 mm thick. Conspecific overgrowths are common. Moderately to highly-elevated circular to elongated monticules have a central cluster of mesopores surrounded by zooecia larger than those in intermonticular areas. Monticules are generally spaced 2 or 3 imm apart, measuring from center to center. Zooecia are generally subangular or subcircular,less commonly angular or circular and are relatively constant in concentration and maxinmum dimension throughout one massive zoarium from which serial peels were made and studied quantitatively. Zooecial wall laminae are generally poorly defined. Zooecial boundaries are narrow and dark or more commonly, obscured by abundant dark and poorly-defined mural lacunae in the thickerwalled zones. The wall laminae commonly are contorted adjacent to the mural lacunae. Cystiphragms are in continuous series throughout the zooecia in massive zoaria. In many frondescent zooaria, cystiphragms are locally larger, separated or absent in the endozone.Serial peels of one massive specimen reveal cystiphragms on the distal side in the prostrate zone and for a moderately short distance above the base, but nearer the zoarial surface, cystiphragmls are conmmonly radially arranged around monticules, on the side of the zooecium nearest the monticule. Cystiphragms are thin, generally closely and evenly spaced in continuous series, but commonly are more-closely and less regularly spaced distally. Diaphragms are comparable to cystiphragms in thickness and are generally planar and perpendicular to the zooecial walls. Diaphragms are developed throughout zooecia and commonly are spaced about the same as or slightly more widely than cystiphragms. Short acanthopores are common to abundant in thick-walled zones. Acanthopores range from those having distinct transparent cores surrounded by cone-in-cone laminae to cone-like flexures of laminae in the zooecial walls lacking distinct cores. Mesospores occur throughout the exozones in all growth habits and are generally absent in endozones. Mesospores are generally smaller and less abundant distally. Very close to the zoarial surface, where zooecial walls are thickened, mesopores commonly are pinched out or filled in so that the number of mesospores can decrease conspicuously distally. In intermonticular areas, mesopore diaphragms are comparable in thickness to zooecial diaphragms. Mesopore diaphragms commonly are more closely spaced than cystiphragms and zooecial diaphragms. Monticules have a central cluster of a few to approximately 40 small mesopores surrounded by zooecia larger than those in intermonticular areas. Mesopore walls and diaphragms are commonly thicker than in intermonticular areas; locally greatly thickened and filled mesopores produce a subsolid center in monticules. Acanthopores commonly are larger and more abundant in monticules than in intermonticular areas.
- Zoarium massive to lobate, surface with conical or somewhat elongate monticules composed of zooecia slightly larger than normal. Mesopores few. Acanthopores small, numerous. Longitudinal section shows a succession of (m) and (im), the former characterized by the thickening of the walls and closer spacing of diaphragms.
Fairly common in the Fairmount of the southern Bluegrass.
- Zoarium irregularly frondescent or sublobate or palmate, rarely submassive; the fronds from 3 to 8 mm. thick, and 30 or 40 cm. high and almost as wide. Surface with closely set, rounded, not conical, often slightly elongated, prominent monticules, from one to two mm. apart. Apertures subequal, even those on the monticules no larger than the others, polygonal, with thin interspaces, about 10 in 2 mm. Mesopores wanting or practically so. Acanthopores wanting. Zoœcia thin-walled, with very numerous cystiphragms and diaphragms.
- Occurrence:—This species appears to begin with the massive form in the lower part of the Fairmount. It becomes abundant in the upper part of the Fairmount and exceedingly abundant in the Bellevue in the vicinity of Cincinnati. In central Kentucky it is abundant in the upper part of the Fairmount. Specimens were collected at Mt. Sterling and Maysville, Ky.
Nickles & Bassler (1900):
- Zoarium massy, lobate or lamellate, incrusting or free; monticules usually present; zooecia prismatic, usually thin-walled, wit cystiphragms both in mature and immature regions; apertures polygonal; mesopores few or wanting; acantopores small, generally numerous
- Corallum in undulated expansions, two to six lines or more thick, often consisting of several layers of corallites, diverging from an imaginary, but not a definite plane and opening on both sides; occasionally massive; surface with rounded, conical or elongated monticules, either conspicuous or only slightly raised; these occupied by corallites either slightly larger or slightly smaller than the average; or else the sides with full-sized, and the summit with smaller corallites; calices of two kinds; large ones polygonal, or sub-polygonal with moderately thickened walls at the surface; small ones moderately numerous, intercalated between the larger tubes, variable in size and shape, but always angular or sub-angular; spiniform corallites variable in number; tabulae of large corallites few and remote; of small corallites numerous and closely set, in both cases all complete and approximately horizontal. (Prodr. De Pal., vol. I, 1950, p. 25; Nicholson, Genus Montic., 1881, p. 104.)
This species is generally regarded as the type of the whole genus Monticulipora inasmuch as it was the first species described by D’Orbigny. There has been considerable discussion as to what was intended by D’Orbigny because there are several species similar externally but differing in other ways. Dr. Nicholson admits that D’Orbigny might have had in mind either this species, his M. molesta, or M. dawsoni. The selection is, therefore, somewhat arbitrary. Mr. Ulrich contends that Nicholson is mistaken in his form and that M. molesta is really M. mammulata D’Orb., while M. mammulata of Nicholson is something else. We have followed Dr. Nicholson in selecting form known as mammulata. It is one of the commonest species of the genus at many exposures of the group in Ohio and Indiana. In the collection of the late Mr. U. P. James is a massive specimen about nine inches in its longer and five inches in it shorter diameter. About half of the longer diameter forms a dome-shaped mass, the surface irregular and covered with small, closely set monticules. Inside are several branches extending downward and spreading out into a wonderfully interlaced mass of frondescent branches. These branches are surrounded by a mass of clay.