This is Mazon Monday post #253. What's your favorite Mazon Creek fossil? Tell us at email:[email protected].
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Pipiscius zangerli is an extinct species of lamprey that lived 307-309 million years ago, during the Middle Pennsylvanian Epoch of the Carboniferous Period. It has a distinctive crown-like mouth comprising a ring of radially arranged teeth. It is known from the Mazon Creek fossil beds located in present-day Illinois. It was described by David Bardack and Eugene Richardson, Jr in the paper "The New Agnathous Fishes from the Pennsylvanian of Illinois", which was published in Fieldiana Geology in June 1977. Due to Pipiscius zangerli's symmetrical features from the middle to both ends, old-time Mazon Creek collectors gave it the nickname "Push me-Pull you".
It was named for Dr. Rainer Zangerl (1912-2004), long-time curator and department chair at the Field Museum. Zangerl was a founding member and President of the Society of Verebrate Paleontology, which awarded him with its highest honor, the Romer-Simpson Medal. There's a very nice dedication to Zangerl by Ray Troll of the Paleo Nerds podcast. Troll is a famous paleo-artist, who calls Zangerl his friend and mentor.
My friend and mentor, Rainer Zangerl, PhD, died last year at age 92. He was appointed as curator of fossil reptiles at The Field Museum in 1945, and served as the geology department’s chair from 1962 until his retirement in 1974.
- Ray Troll, 2005
I’m a fish-obsessed artist living in Alaska, so it’s unusual that I would befriend a retired scientist living on an Indiana farm. But when your work leads to the obscure netherworld of prehistoric sharks, there are only a handful of people to turn to.
I saw a profoundly puzzling fossil shark at the Natural History Museum of Los Angeles County in 1993. Helicoprion looks like a spiral snail shell at first, but a closer look reveals finely serrated shark teeth that decrease in size as the coil winds inward. I wondered how the teeth grew and how it ate, yet
Dr. Zangerl told me about even weirder sharks that once inhabited North America, and I began drawing them. I visited him in 1994, an unforgettable time discussing the wonders of life on our planet, eating his tasty homemade bread, and hunting for fossils in his front yard. (Not surprisingly, Dr. Zangerl had built his home on a great fossil deposit.)
Dr. Zangerl emigrated from Switzerland in 1939. He had a wonderful way with words, trilling his Rs and describing ancient sharks as “fierce cr-r- r-itters.” He published more than 60 scientific papers on a variety of subjects and wrote a now- classic memoir on the Pennsylvanian black shales that permeate the Midwest. Over a steak dinner at a roadside diner, he casually mentioned that he had translated Willi Hennig’s Phylogenetic Systematics with a friend in the 1960s—triggering a revolution in systematic biology.
Dr. Zangerl pointed out several Indiana quarries where he had split thousands of rocks in search of ancient life. Like a 5-year-old school kid at the master’s knee, I asked which was his favorite of all the fantastic animals he had discovered.Without hesitation he said, “Ornithoprion, a very strange cr-r-r-itter indeed. It had a pointed snout and a lower jaw shaped like a bony probe.All we ever found was the head, but what a head it was!”
Inspired by my sojourn to old “Dr. Z,” I drew like a madman back in Alaska and took extra care in reconstructing Ornithoprion. I sent him some copies and cautiously called a week later. “Well, um ... what did you think of the drawing?” I asked. “It’s absolutely perfect. You really brought zat cr-r- r-itter to life,” he trilled. Now, every time I look at that drawing, I remember my pal, Dr. R-r-r-ainer Zanger-r-r-l, and smile.
In "The New Agnathous Fishes from the Pennsylvanian of Illinois", the referred specimens list many familiar names.
Referred specimens.-FMNH: PF 8345, one piece; PF 8346, part and counterpart; PF 7514, part and counterpart. Sobolik Collection, P 33, part and counterpart. Piecko Collection: HTP 153, one piece: HTP 5099, part and counterpart; HTP 5431, one piece. Kimball Collection, part and counterpart. Sherman Collection, 1180, part and counterpart; Douglass Collection 604, part and counterpart.
Introduction and description from "The New Agnathous Fishes from the Pennsylvanian of Illinois"
Among the several well-preserved but perplexing animals in the Middle Pennsylvanian (early Westphalian D) Essex fauna of north- ern Illinois (Richardson and Johnson, 1971) are two which appear to be chordates at the agnathan level of organization. Both show elab- orate oral and pharyngeal structures without analog among known chordates. Some cranial elements are indicated by darkly stained patches on the plane of the concretions, but, if cartilaginous skeletons were developed, they were uncalcified and less substantial than those of Mayomyzon, a lamprey (Bardack and Zangerl, 1971) found in the same fauna. It is quite possible that the two animals described here are larvae with a still unknown adult phase.
The Essex fauna lived on a delta at the end of an embayment in the northeastern corner of Illinois Basin. Fine clastic material, with occasional increments of sand, was brought in by streams that flowed for long distances through a coal swamp; in and adjacent to the streams lived animals of the Braidwood fauna. The vertebrates of both faunas are represented almost entirely by small individuals; the presence of large and presumably mature individuals is indi- cated by scattered scales and bones of large lungfishes and rhipidistians plus large coprolites and rare teeth and cartilage elements of sharks. The delta environment, both subaerially and subaqueously, provided suitable habitat for young animals. The specimens here described occur in Pit Eleven of the Peabody Coal Company in Will and Kankakee counties. Within this pit, one traverses a sequence of ancient environments from shallow marine at the south to a marginal shore zone at the north, and in the band of other pits farther north a subaerial zone. Local concentrations of various members of the fauna indicate that local habitats must have varied in depth, salinity, warmth, vegetational cover, turbidity, and other environmental parameters. The preponderance of small forms among the fishes (as well as the tetrapods, eurypterids, and xiphosures) suggests that this portion of the delta provided a modicum of protection from rapacious adults.
Description. This account is based on all 10 known individuals (fig. 1). Specimens range in length from about 4 to 6.5 cm. and body depth varies from 0.7 to 1.4 cm. About half of the specimens, predominantly the shorter individuals, exhibit a plump ventral distension of the body. This ventral expansion may be a remnant of a yolk sac similar in form to that of a late stage of anuran embryonic development (fig. 2). Larger individuals are elongate and possibly circular in cross-section. Most individuals are preserved in lateral aspect, although the head end is often twisted so that the characteristic mouth structure is viewed dorsally or ventrally (fig. 3). Although no distinct hard parts are preserved, certain consistent pigmentation patterns, depressions and ridges, particularly in the mouth region, permit tentative reconstruction of some internal anatomy.
The head as a whole is not topographically distinguished from the body. Anteriorly, between the mouth and the eye, the head appears rather flexible, as suggested by the rotation of the mouth parts in laterally preserved individuals. A notch in the dorsal and ventral margins of the head anterior to the eye, ventrally extended profile of the oral part of the head and some darkly stained areas above the mouth all suggest the presence of an oral hood analogous to that of modern adult lampreys.
The mouth margin and the wall of the mouth cavity were surrounded by a firm substance that has not been preserved but has left a distinct impression (figs. 4, 5). Proximally, the mouth structure comprises a collar in the shape of a thin truncated cone, its wall composed of 23 rectangular lamellae (collar lamellae), with thin radial vanes (collar vanes) projecting into the lumen of the oral cavity at the junctions between lamellae. Distally the collar vanes terminate in a knob-like thickening. The lamellae and vanes on the anterior aspect of the collar are somewhat longer and wider than those on the posterior. A deep pit (collar pit) is excavated into the junction of each pair of collar lamellae, on the outer surface, opp site each vane; these pits are very pronounced in the anterior aspect and become faint or absent toward the posterior aspect. An irregular system of polygonal ridges on the outer surface of the lamellae suggests that either the substance was cracked by volume loss during decay or the lamellae were compound.
Distally, the collar articulates at about a right angle to a more elongated and distally expanded set of 23 plates, forming a circle that is gently inflected to embrace the margin of the mouth. Distally, the diameter of the circle is about twice the proximal diameter of the collar. The circle plates, like the structures of the collar, are larger in the anterior aspect. A plate lies opposite each collar vane. Each plate is roughly triangular in outline, thickened just beyond its junction with the collar, then thinning and narrowing distally. The thickened regions of neighboring circle plates abut against each other and probably could pivot on this abutment. Each plate also bears on its midline a radial vane (circle plate vane) projecting into the lumen of the oral cavity. The vane terminates in a thickening adjacent to that of the corresponding collar vane. A triangular area with its broad base at the distal end of the mouth lies between each pair of circle plates. It, too, has a central vane on the buccal surface.
This complex mouth structure must have been operated by a set of muscles. The collar formed a fixed diameter, with little or no potential for expansion or contraction; however, a set of circumferential collar muscles might have provided for a limited amount of expansion. Most of the movement of the mouth structure was confined to the circle of plates. Muscles running between the terminal knob-like thickenings of the collar vanes and plate vanes could draw the plates inward. Circumferential muscles between adjacent circle plates assisted in constricting the distal opening of the mouth. Restoration of an open position could have been achieved by muscles or ligaments extending between the collar pits and the thickenings of the circle plates.
Behind the mouth, several specimens exhibit an impression of a slender tube followed by an expanded cavity with a series of ridges and grooves. We interpret this as a pharyngeal tube and pharyngeal pouch surrounded by muscles and capable of pumping nutritive material into the animal. Coupled with the mouth structure, it provided a strong feeding mechanism capable of ingesting detritus or small invertebrates.
A pair of eyes represented by discs of pigmented material with a small, clear central area doubtlessly occupied in life by a lens, lies above the pharyngeal pouch. Behind the eyes a slightly anteroposteriorly expanded bulbous structure may represent the otic capsule. Beginning behind the pharyngeal pouch and extending below and behind the otic capsule lies a series of at least four dorsoventrally expanded clefts (clear, unpigmented areas). Each is surrounded by darkly stained areas which are most emphatically marked ventrally. In some specimens these pouches are small and closely packed, while in others they occupy a broader area. These clefts and surrounding tissues are probably the gill pouches. We are somewhat puzzled by the limited number of such respiratory structures in an agnathan. Possibly the entire set is not well preserved or more may be added ontogenetically. The latter alternative is unlikely, however, as living Petromyzon show all gill pouches by embryonic stage 15 (Piavis, 1971)-at about 0.5 cm. body length.
Several other deeply pigmented areas, especially in the head region, are indicative of developing cartilaginous or other head structures. None shows a sufficiently consistent pattern in several specimens to enable us to assign it to a specific structure. Some of these pigmented areas, especially around the eyes and below the gill pouches, suggest that thick, rigid structures would be formed.
No distinct features of the anterior part of the digestive cavity are indicated by pigmentation patterns as in Mayomyzon. Two specimens (FMNH: PF 8344 and PF 8345), however, display an elongate tubular swelling which is rounded at its anterior end about midway along the length of the body and tapers toward the rear margin of the body cavity. This expanded area is filled with fine-grained mineral material somewhat different from that of the rest of the concre- tion and characterized by several irregular vertical grooves and folds. It probably represents the digestive tube; the folds and grooves suggest muscular folds of the tube wall. It is probably not a coelom filling because it is surrounded by large, clearer spaces and lies well below a darkly pigmented region which should be expaxial musculature.
Myomeric segmentation is evident at the rear end of the body. The segments are especially distinct across the posterior end of the body cavity, where more than 20 may be counted. While dorsal and ventral ends are indistinct, the myomeres appear in the form of a posteriorly opened V with a shorter upper than lower arm. There are neither paired fins nor a distinct caudal fin. There is a short dorsal fin at the posterior end of the body, supported by at least 10 slender rays.
Pipiscius zangerli appears on page xx of Jack Wittry's "The Mazon Creek Fossil Fauna".
Pipiscius zangerli Bardack and Richardson, 1977
Pipiscius zangerli is the most unusual of all the Mazon Creek fish, and nothing quite like it has been found elsewhere. It has a circular mouth consisting of two rows of plates. No other mouth parts such as teeth or any type of hard parts have been observed. P. zangerli is thought to have fed on bottom-dwelling animals and/or decaying organisms.
These fish most often appear to have distended stomachs and blunt, humped tails. If not for the circular mouth at the other end, the tail could be mistaken for the head. This, and the fact that the animal is nearly symmetrical from the middle out toward the ends, led early collectors to give this fish the nickname Push me-Pull you.
Specimens
From Wittry, showing the mouth
Also from Wittry
Mouth of the holotype from "The New Agnathous Fishes from the Pennsylvanian of Illinois"
FIG. 4. Pipiscius zangerli, n. g., n. sp. Impression of inner surface of mouth, as viewed from within the animal, anterior to upper left. FMNH PF 8344, holotype, X12.5
Holotype FMNH PF8344
