Trypanosoma (Haematomonas) sheppardi Dias, 1951 emend. Jordaan, du Preez

Jordaan, Bernard J., H., Louis, Preez & Netherlands, Edward C., 2024, Revisiting the diversity and phylogenetic relationships of trypanosomes (Trypanosoma) infecting pelomedusid (Pelomedusidae) freshwater turtles in Southern Africa, Zoological Journal of the Linnean Society 202 (1), pp. 1-13 : 6-7

Redescription of Trypanosoma (Haematomonas) sheppardi Dias, 1951 emend. Jordaan, du Preez & Netherlands

Trypanosoma sheppardi Dias, 1951

Type host: Pelusios sinuatus Smith, 1838 ( Testudines: Pelomedusidae ) (syn. Pelusios sinuatus zuluensis ).

Type material: No type material was designated by Dias (1951) in the original description of T. sheppardi . Therefore, we designate a hapantotype, one peripheral blood smear from Pelusios sinuatus host deposited in the protozoan collection of the National Museum, Bloemfontein, South Africa under accession number NMB P 1026 (RE210311A3). Other voucher material belonging to the type series, one blood smear from Pelusios sinuatus host deposited in the protozoan collection of the National Museum , Bloemfontein, South Africa under accession number NMB P 1027 (RE210311B1) .

Type locality: Maputo River , Catuane region, Maputo, Mozambique ( Dias 1951) .

Localities in this study: Water pan 0.6 km south of the Maputo River (26°51 ʹ 55.9″ S, 32°09 ʹ 59.8″ E), Ndumo Game Reserve, KwaZulu-Natal, South Africa . Nyamiti Pan (26°54 ʹ 00.4″ S, 32°15 ʹ 46.4″ E), Ndumo Game Reserve , KwaZulu-Natal, South Africa .

Site of infection: Peripheral blood.

Vector: Unknown.

Stages in vector: Unknown.

Representative DNA sequence: The sequence data specifically associated with T. sheppardi (upon which the present biological redescription is based) have been submitted to GenBank and are as follows: Nuclear 18S rDNA (nu 18S) partial sequences PP826326 (RE210311B1) and PP826327 (RE210311A3).

Description: Measurement range shown in micrometres (mean ± SD). Body length 43.68–66.66 (56.84 ± 6.4) (N = 15) and body width 4.25–11.86 (7.3 ± 2.33) (N = 15); with a body shape index of 4.48–12.84 (8.44 ± 2.35) (N = 15). Nucleus length 2.78–6.7 (4.91 ± 1.06) (N = 15) and nucleus width 1.5–4.02 (3.04 ± 0.76) (N = 15); with a nuclear index of 1.16–2.46 (1.66 ± 0.36) (N = 15). Undulating membrane width 1.27–2.32 (1.83 ± 0.25) (N = 14) and number of undulations 7–12 (9.47 ± 1.41) (N = 15). Kinetoplast length 0.6–1.09 (0.94 ± 0.13) (N = 15) and kinetoplast width 0.49– 0.7 (0.59 ± 0.07) (N = 15). Mid-nucleus to anterior body end distance 27.36–44.48 (35.7 ± 4.55) (N = 15) and mid-nucleus to posterior body end distance 12.12–27.23 (22.81 ± 3.96) (N = 15). Kinetoplasttoanteriorbodyenddistance 37.57–61.72 (50.81 ± 6.44) (N = 15) and kinetoplast to posterior body end distance 1.51–8.93 (6.28 ± 1.9) (N = 15). Kinetoplast to mid-nucleus distance 4.69–20.08 (16.85 ± 4.02) (N = 15). Free flagellum length 11.42–11.42 (11.42 ± 0) (N = 1). The nucleus and kinetoplast are positioned 52.03–75.6 (62.96 ± 5.79)% (N = 15) and 85.49–99.85 (89.31 ± 4.06)% (N = 15) from the anterior body end, respectively.

Remarks: This trypanosome had a broad body, thicker in the middle, with tapering anterior and posterior ends ( Fig. 2 ). The cytoplasm stained uniformly a faint purple, with few cytoplasmic vacuoles visible. The nucleus was round and stained light pink, with a nucleolus occasionally visible. A relatively long flagellum was present but was often obscured. The morphology of this trypanosome was most similar to the description of T. sheppardi Dias, 1951 .

The body dimensions of the trypanosome in the present study were more variable, but were within the measurement range described by Dias (1951) for T. sheppardi , measuring 43.68–66.66 by 4.25–11.86 µm, and 48.9–49.4 by 7.8–8.8 µm, respectively. Although the average body length of 56.84 ± 6.4 µm for this trypanosome was slightly larger than the original description of T. sheppardi , the average width of 7.3 ± 2.33 µm was close to the lower range in the original description, and the body shape index was similar, measuring 1.66 ± 0.36 vs. 1.6 in the original description. The kinetoplast to nucleus distance of this trypanosome, 16.85 ± 4.02 µm, was within the range originally described for T. sheppardi of 16.1–17.6 µm. The mid-nucleus to posterior end distance of this parasite was within the range of the original description of T. sheppardi , measuring 22.81 ± 3.96 and 20.2–22.95 µm, respectively. Dimensions of the nucleus of this parasite were 4.91 ± 1.06 by 3.04 ± 0.76 µm, which are consistent with the range of T. sheppardi , 4.4–4.9 by 2.8–3.1 µm, in the original description. The position of the kinetoplast from the anterior body end of this parasite corresponded to the position calculated from the original description of T. sheppardi , of 89.31% ± 4.06% and 84.45–90.28%, respectively. The body of this species (excluding the undulating membrane) was proportionately broader when compared with the morphometrics of another similar species, T. neitzi from the present study, with a body shape index of 8.44 ± 2.35 vs. 9.16 ± 1.73. Furthermore, the nucleus of T. neitzi was positioned closer to the middle of the body in comparison to this trypanosome, 55.71% ± 4.59% vs. 62.96% ± 5.79% from the anterior, respectively.

The trypanosome in the present study was described from the same host species as the type host of T. sheppardi , namely the serrated hinged terrapin, Pelusios sinuatus (syn. Pelusios s. zuluensis). Furthermore, host specimens in the present study were collected within 10 km from the type locality and same river system, the Maputo River, originally described for T. sheppardi . Therefore, for the aforementioned reasons, this species is redescribed as Trypanosoma (Haematomonas) sheppardi .

Diversity of turtle trypanosomes • 7

Figures

Figure 2. Trypanosoma sheppardi: commonly observed trypomastigote forms.Scale bar: 10 µm. Arrowheads show kinetoplast (A, B); arrows show flagellum (D, E) and undulating membrane (C, F); nuclei are indicated by ‘n’ (B, D).