大鼻龙类（Macronaria）是个蜥脚下目演化支，生存于中侏㑩纪巴通阶到晚白垩纪，发现于现在的北美洲、南美洲、欧洲、亚洲、以及非洲、澳洲等地。大鼻龙类意为「大型鼻孔」，指的是头部上方的大型鼻孔，可能作为扬声器使用。在2005年，保罗·塞里诺重新将大鼻龙类演化支定义为：与萨尔塔龙（Saltasaurus loricatus）亲近，而离长梁龙（Diplodocus longus）较远的所有物种。大鼻龙类包含两个主要演化支：圆顶龙科、巨龙形类。巨龙形类包含腕龙科与泰坦巨龙类，是最大型的蜥脚类生物群之一，也包含了地表上曾出现过最长、最高、最巨大的恐龙。

Macronaria is a clade of sauropod dinosaurs from the Middle Jurassic (Bathonian) to Late Cretaceous Periods of what are now North America, South America, Europe, Asia, Africa and Australia. The name means 'large nostrils' (from scientists' reinterpretation of Greek makros, 'long,' as 'big,' and Latin nares, 'nostrils'), in reference to the large nasal openings high on the head that probably supported fleshy resonating chambers. Macronaria consists of a single main group, Titanosauriformes, along with several more basal taxa. Titanosauriformes in turn contains the brachiosaurids and the titanosaurians and is one of the largest sauropod groups, which also contains some of the longest, tallest and most massive dinosaurs of all time.