梁龙超科（Diplodocoidea）是蜥脚下目恐龙的一个超科，包含了某些地表上曾出现过最长的动物，例如：超龙、梁龙、迷惑龙、以及双腔龙。大部分的梁龙超科恐龙拥有非常长的颈部、以及鞭状的长尾巴，四肢与体型细长，头部形状类似马头，钉状牙齿只位于颌部前部；然而，叉龙科是蜥脚下目之中，唯一一科重新演化成为短颈部的恐龙，牠们的短颈部被推论为以低高度植被为食的适应演化。这种短颈部的适应演化在短颈潘龙身上达到高度特化。

一个针对梁龙超科的口鼻部外形、牙齿磨损状况的研究，提出迷惑龙、梁龙、尼日尔龙、雷巴齐斯龙具有方形的口鼻部、牙齿有大面积的凹处、牙齿有接**行的磨损痕迹，显示牠们是以接近地面、无特定食物来源的植被为食；而叉龙、春雷龙、拖尼龙的口鼻部狭窄，叉龙的牙齿磨损痕迹粗糙，显示牠们是以中等高度植被、特定植物为食。

Diplodocoidea is a superfamily of sauropod dinosaurs, which included some of the longest animals of all time, including slender giants like Supersaurus, Diplodocus, Apatosaurus, and Amphicoelias. Most had very long necks and long, whip-like tails; however, one family (the dicraeosaurids) are the only known sauropods to have re-evolved a short neck, presumably an adaptation for feeding low to the ground. This adaptation was taken to the extreme in the highly specialized sauropod Brachytrachelopan. A study of snout shape and dental microwear in diplodocoids showed that the square snouts, large proportion of pits, and fine subparallel scratches in Apatosaurus, Diplodocus, Nigersaurus, and Rebbachisaurus suggest ground-height nonselective browsing; the narrow snouts of Dicraeosaurus, Suuwassea, and Tornieria and the coarse scratches and gouges on the teeth of Dicraeosaurus suggest mid-height selective browsing in those taxa. This taxon is also noteworthy because diplodocoid sauropods had the highest tooth replacement rates of any vertebrates, as exemplified by Nigersaurus, which had new teeth erupting every 30 days.