The Search for the Intersection of Form and Function: Looking for Clues into What Has Determined How, Why, and When Animals Came to Move the Way They Do.

Abstract

Like most young children, I dreamed of what I would be when I grew up. There were two things I envisioned. The first was to play on the Brooklyn Dodgers baseball team (Laitman, 2018). I saw myself as an infielder, yearning to be part of the smooth and fast group that boasted Jackie Robinson, Pee Wee Reese, and Gil Hodges. I wanted my arms to throw a ball with the precision, and legs to move with the grace, that theirs unfailingly did. When the Dodgers left Brooklyn after the 1957 season for some place called “Los Angeles” I was devastated. I'm still in therapy over this. I have visited, worked in, or lectured at, universities in well over a hundred cities but, for whatever reason, never that place (my people hold grudges.). My second dream was to study dinosaurs. Not some old bones, mind you, the actual dinosaurs, which I thought were still alive (I never said that I was a particularly bright child; no one told me that they were dead!). I thought that dinosaurs still existed in New Jersey. This is not as strange as it might sound when you understand how a New Yorker views geography. The north is bounded by Yankee Stadium in “Da Bronx” (there are wilds above with “headless horsemen” around Sleepy Hollow, but we don't go there); the South is Coney Island with a further outpost called “Miami” (or the sixth boro; we see this as part of New York) where many go when the end beckons (they just “know”; sort of like elephants); to the east is the great ocean and the “old country” (Ireland, Italy, pogroms); and to the west, the mighty Hudson River. Beyond that is the wilderness known as “Joysey.” (BTW, so you don't think I'm totally off, it so happens that the first substantial skeleton of a fossil dinosaur found in North America was from, you guessed it, New Jersey. The great Joseph Leidy, Professor of Anatomy at the University of Pennsylvania and first President of the American Association of Anatomists, reconstructed the cranial and post-cranial bones of a dinosaur that he named Hadrosaurus, the duck-billed dinosaur, back in 1858; Laitman, 2009.) You can imagine my shock when I discovered that dinosaurs no longer roamed the streets of Hoboken, Bayonne, or Newark. This, and being ejected from the American Museum of Natural History in New York for climbing on a brontosaurus (long story; see Laitman, 2010), ended my dinosaur career before it began. By the time I was 7 my dreams were crushed. Fortunately, I discovered that monkeys were still around and began to think that I could one day study them: in the wild, in jungles, maybe, even wearing one of those neat safari helmets. Who needed old dino bones when you could study gorillas, baboons, or, those really cool dudes called “lemurs?” When I finally decided upon graduate school (my various aptitude tests showed I had none; hence grad school). I chose Yale, as it would allow me to study both anatomy (I was good at taking things apart) and anthropology. Along with the latter area came my chance to experience living primates first-hand, up-close and personal. Within a half year of ingesting the wonders of New Haven I was preparing to spend months in Madagascar with Alison Richard (now Dame Alison) one of the brightest, most tenacious, and overall impressive people I've ever known. Indeed, she went on to become Provost of Yale and later Vice-Chancellor of Cambridge, and was knighted. She also knew everything, and I mean everything, about working in forests and jungles as she had studied lemurs, her specialty, and a group I was particularly fascinated with. It was off to Madagascar for me in late spring of 1974. The relative I was assigned to study was the ring-tailed lemur, Lemur catta, given its scientific name due to its cat-like appearance and purring sounds they often make. I think Allison assigned this group to me because they: (a) are not that hard to find, (b) usually get up in the late morning, and (c) then sun-bathe a good part of the day. I wasn't going off in search of some elusive, dangerous beast. These lemurs were as close to my Florida relatives as I could get, which is why I think she chose them for me. For those of you who are not familiar with lemurs, they are amongst the most varied (over 100 species), and fascinating, of all of our primate relatives. No disrespect to our ape sisters and bros, or the myriad of monkeys climbing trees everywhere from India to the Congo to the Amazon. Lemurs are just among the coolest of our group (see the Madagascar movies if you don't believe me). They range from large Indris almost 4 feet with legs extended with some weighing over 20 pounds (there were subfossil giant lemur species the size of gorillas that lived until only 500 years ago!); to the smallest of all primates, mouse lemurs (the head and body of some are all of 2½ inches long; so small a group can fit in your palm); to the weirdest looking of all primates (ok, not to its mother) the aye-aye; to those that eat their own feces (Lepilemur, the sportive lemur; not mentioned in the movies). Isolated for millennia on the exotic island of Madagascar lemurs have expanded into every niche possible. Lemurs have fascinated many, as they did me, because you could find in the extreme beauty of an island devoid of the big, mean beasties of mainland Africa (e.g., no lions, leopards, hippos, or rhinos) and no scary vipers or mambas or cobras (scared of snakes, too) an extraordinary diversity of body forms and how they evolved over time to interact with their environment. Lemur world provides one incredible natural experiment. Some species, like the sifakas (genus Propithecus, they make an alarm call that sounds like “shi-fak”, hence the name) move by vertical clinging and leaping, in which they maintain an upright position of the trunk as they leap from tree to tree. It's a magnificent sight to witness these extraordinary relatives bounding in vertical posture among trees. Members of the genus Lemur itself, like the ring-tailed group I hoped to study, are both quadrupedal (four footed) as well as quadrumanous (four handed). A brown lemur once came over to where I was eating lunch and threw things at me with both hands while he took my sandwich with his right foot! Inter-specific abuse! Some lemurs, like the bandro (Haplemur alaotrensis) can even swim! Recalling the remarkable diversity of these lemurs—and their varied modes of movement and manipulation—is a natural segue to this second volume of our Special Issue, “Behavioral Correlates of Muscle Functional Morphology.” This volume will focus on exploring the interface of anatomy and function in the post-cranial world of movement, manipulation, and locomotion, much as the first volume did in exploring cranial biology (Hartstone-Rose and Santana, 2018; Laitman, 2018; Laitman and Albertine, 2018). As with the first volume, this one is Guest Edited by anatomists/functional morphologists/comparative biologists Adam Hartstone-Rose of North Carolina State University, Damiano Marchi of the University of Pisa, and Sharlene Santana of the University of Washington and the Burke Museum of Natural History and Culture. This Special Issue grew out of a Symposium entitled “Muscle functional morphology beyond gross anatomy” held at the 11th International Congress of Vertebrate Morphology in 2016 in Bethesda, Maryland and organized by Drs. Hartsone-Rose and Marchi. As I have commented on the expertise of our intrepid Guest Editors previously (Laitman, 2018), I won't repeat myself here save to again thank them, and acknowledge their individual and collective energies in assembling this volume as they so successfully did the last. In this volume one will see an extraordinary view of the interface of muscle, function, and behaviors from the “muscles perspective.” As Marchi and Hartstone-Rose (2018) well articulate, the place in nature of muscles has long been overshadowed in studies of movement by focus upon bones. Muscles have been acknowledged, but often almost as an afterthought, as attachments to accompany and effectuate osteological forces. Marchi and Harstone-Rose's authors note the gradual evolution in respect for, and understanding of, the myological world and how this gradually came about. Indeed, they pay homage to one of our own, the great anatomist and electromyographer Basmajian (1962, 1972), also a past-president of this journal's parent body, the American Association of Anatomists. Basmajian was at the forefront of giving muscles and their biology a “place in the sun” with his insightful work starting in the 1950s. The papers in this volume elegantly stride over a lot of territory, handling both aspects of upper extremity and lower extremity issues. An extensive array of vertebrate species are explored, with lizards slithering, mice scurrying, bats flapping, martens maneuvering, and ponderous apes knuckle-walking through these pages. Non-human primates of many species are in abundance. Even we humans make appearances both in discussions of upper and lower musculature. Techniques highlighted range from elegant dissections to virtual dissection to employment of cutting-edge Contrast-Enhanced-Computed Tomography. Many of the studies present modeling experiments to assess differences among members of the same, or closely-related, species assessing muscle/functional differences in differing habitats. As with the first volume, underlying the science presented are hypotheses testing the seminal questions of the relationship of form to function. Again, many may be unanswerable as they often approach metaphysical unknowns at the root of existence itself. Nevertheless, led by these intrepid Guest Editors, the work within takes us to the smoldering core of these eternal questions. It is science at its best. As for me, my dream of studying the graceful movements and manipulations of Malagasy lemurs for my career never came to fruition. After many months of trying to find arguably the least elusive of our primate relatives—my Miami dwelling older sister moves more than some of these Lemur catta—I was giving up. Future Dame Alison surely realized that I didn't have the “jungle gene.” Indeed, as I sat, forlorn, never having found my particular conspiracy of lemurs (how about that for a name for a group of lemurs? The name lemur itself comes from the Latin for “spirits of the dead”) I saw some of them moving down from the high branches. Ecstatic, I took my cameras and dashed (I could dash in those days) after them, constantly looking upwards so I would not loose sight of the lemurs until…until I ran right into a massive forest of Opuntia madagascariensis, prickly pear trees, relatives of cacti. I became impaled upon the massive spines that were everywhere (these plants are used in Madagascar for fortifications!) I screamed so loudly I think that I could have been heard in Brooklyn. I must have looked like some sort of stuck pig, with every movement forcing those darn spires deeper into me (I still have many scars). And as I squirmed, in pain, wishing I could be any place on Earth but here, the lemurs that I had been trying so hard to find, to see, to understand, descended from on high and sat just above my head staring at me. As if that was not bad enough, one retrieved my sack, took my sandwich, perched his fuzzy butt on an Opuntia branch (how did it not hurt him?) and literally ate my lunch! (I would have marveled at the wonderful nexus of muscle form and function that led him to manipulate every morsel of my sandwich, but I was in too much pain!). They just stared and stared at me for what seemed like hours. I could see their little minds thinking, “What a total schlimazel. What a loser!” There is something indescribable about interspecific humiliation. I was eventually rescued. But, to this day, whenever I visit the Bronx Zoo, I think the lemurs look at me funny as if they know something about my failed past.