"首長龍" meaning in Japanese

{
  "lang": "Japanese",
  "lang_code": "ja",
  "pos": "soft-redirect",
  "redirects": [
    "首長竜"
  ],
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "Japanese terms with non-redundant non-automated sortkeys",
          "parents": [],
          "source": "w"
        }
      ],
      "id": "en-首長龍-ja-soft-redirect-47DEQpj8",
      "tags": [
        "no-gloss"
      ]
    }
  ],
  "word": "首長龍"
}

{
  "lang": "Japanese",
  "lang_code": "ja",
  "pos": "soft-redirect",
  "redirects": [
    "首長竜"
  ],
  "senses": [
    {
      "categories": [
        "Japanese terms spelled with 長 read as なが",
        "Japanese terms spelled with 首 read as くび",
        "Japanese terms spelled with 龍 read as りゅう",
        "Japanese terms with non-redundant non-automated sortkeys"
      ],
      "tags": [
        "no-gloss"
      ]
    }
  ],
  "word": "首長龍"
}