埼玉県立自然史博物館研究報告　第４号 (1986)

埼玉県秩父地方におけるホンドタヌキ
Nyctereutes procyonoides viverrinus TEMMINCK
の年齢構成と歯数変異

町　田　和　彦
埼玉県立秩父東高等学校
斎　藤　　　貴
埼玉県立松山高等学校

ま　　と　　め
　埼玉県秩父地方で捕獲されたホンドタヌキNyctereutes procyonoides viverrinus TEMMINCKの頭骨を用いて，年齢構成，歯数変異，頭骨測定値を検討した．タヌキは1984年12月〜1985年1月の狩猟期間中に捕獲された137個体である．
1．上顎犬歯を年齢査定に用い，へマトキシリン染色でプレパラート標本を作成した．年齢構成は Age class I が最も多く，78.6％を占めていた．平均年齢は1.02±0.13歳であった．捕獲個体に若齢個体が多く含まれていることがわかった．
2．歯数変異は137個体中26個体（19.0％）にみられた．欠如歯は上顎では第1前臼歯，下顎では第3臼歯・第1前臼歯で多くみられた．過剰歯は，上顎では右第2臼歯の後位，下顎では右第3臼歯の後位にみられた．


Fig. 2. Examples of missing teeth in tipper and lower jaw.
　　A : First premolars were missing in right and left tooth row.
　　B : First premolar was missing in left tooth row.
　　C : Third inciser in right and second inciser in left were missing.
　　D : Third molar was missing in left.

Age Structure and Dental Numerical Anomalies of the Raccoon dogs,
Nyctereutes procyonoides viverrinus TEMMINCK, in Chichibu District,
Saitama Prefecture

Kazuhiko MACHIDA
Chichibu Higashi High School, Chichibu, 368 Japan.
and
Takashi SAITO
Matsuyama High School. Higashimatsuyama, 355 Japan.

Abstract The study of age structure and dental numerical anomalies of raccoon dogs was carried out with 137 skull bones in Chichibu district, Saitama Prefecture. Skull bones were collected during the hunting season of December 1984 to January 1985. The age was determined by the cementum layer method. Age structure consisted of age class I to age class VII. Mean±standard error of ages was 1.02±0.13 years. First age class was 78.6 % of the total. The oldest was age class VII (6.5 years old). Dental anomalies occurred in 19 % in upper and lower jaws of 137 specimens, 17.5 % of these was missing and supernumerary in 1.5 %. The first premolar teeth in the upper jaw and the third molar teeth in the lower jaw were most commonly absent.

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