Makatinus africanus, Girgan & Marais & Fourie & Tiedt & Swart, 2019

Girgan, Chantelle, Marais, Mariette, Fourie, Hendrika, Tiedt, Lourens & Swart, Antoinette, 2019, Description of two new species, Aphanolaimus strilliae n. sp. (Nematoda: Aphanolaimidae) and Makatinus africanus n. sp. (Nematoda: Aporcelaimidae), and SEM observations on three known species from freshwater sources in the Telperion Nature Reserve (Mpumalanga, South Africa), Zootaxa 4651 (2), pp. 201-234 : 212-216

Makatinus africanus n. sp.

Figures 7 & 8

urn:lsid:zoobank.org:act:D3AB1A3C-9B32-4C6D-BF5C-E6EB16A48AF2

Measurements: Table 3

Description: Female (n = 6): Habitus strongly curved ventrally. Body 3228–4128 μm long and moderately thick (a = 30–39). Cuticle 6–7 μm thick in oesophageal region, 7–11 μm at mid–body and 9–11 μm on dorsal side of tail. Cuticle consisting of two distinct layers, a thin outer layer and a thicker inner layer with prominent radial lines that end as fine punctations on the outer surface. Lateral chord 15–20 μm wide, occupying about 15–20% of the corresponding body width at mid-body. Three dorsal and three ventral pores always present at level of odontostylet. The dorsal pores (6–8 pores) are always restricted to the oesophageal region, whereas the ventral pores (24–33 pores) are distributed over the entire body, with 12–16 in oesophageal region. Lateral pores abundant and distributed over entire body, four at level of spear and 12–16 in oesophageal region. Lateral pores over rest of body difficult to distinguish, less distinct due to musculature of body and presence of lateral chord. Lips amalgamated, lip region set off by slight constriction, 6–10 μm high and 27–29 μm wide. Amphid stirrup shaped, aperture 11–14 μm wide, occupying less than half corresponding body width. Odontostylet strong, 31–34 μm long (measured medially from apex to base of dorsal side) and odontophore 52–65 μm long. Odontostyle aperture occupies 60–70% of the total odontostyle length. Guide ring simple, situated 12–18 μm from anterior end. Oesophagus muscular, 747–882 μm long, gradually expanding in posterior half, basal expansion more muscular, 51–61 μm wide at its widest point. Oesophageal gland nuclei obscure due to muscular basal expansion. Nerve ring not observed. Cardia 32–37 μm long, tongue-like expansion at base of oesophagus. Genital tract didelphic-amphidelpic with both branches equal in length. Vulva situated at 47–52 % of the total body length. Vagina more than half the corresponding body width, consisting of 4–6 μm long pars distalis vaginae, 12–18 μm pars refringens vaginae and 37–57 μm pars proximalis vaginae. Pars refringens vaginae consists of two large sclerotized pieces. Uterine eggs observed in most females, measuring 118–124 μm long and 62–65 μm wide. Ovijector muscular and distinct. Uterus long and complex in structure consisting of two oval structures containing sclerotized structures / spines. First oval structure located at junction of ovijector and uterus, second structure smaller, located just before pars dilatata uteri. Pars dilatata oviductus distinct with few sperm cells. Oviduct distinct, ovaries reflexed, typical of dorylaimids. Oocytes arranged in single row except in growth zone. Length of pre-rectum 113–167 μm, that of rectum 63–76 μm. Tail short, 30–43 μm long, with digitate extension, 4–7 μm long. Two caudal pores present.

Male: Unknown.

Diagnosis and relationships: Makatinus africanus n. sp. is characterised by a large body (3228–4128 μm long, a = 30–39 wide), slightly set off lip region with amalgamated lips; 31–34 μm long odontostyle; long tongue-shaped cardia, and stout, short tail (30–43 μm long) with a small peg / digitate extension. Male absent.

According to the latest compendium of the genus Makatinus ( Peña-Santiago & Varela 2017) there are eight valid species. The descriptions of the type females of these species were compared to Makatinus africanus n. sp. and the following differences were observed. Based on the presence of a digitate structure on the tail, the closest related species to Makatinus africanus n. sp. is M. punctatus Heyns, 1965 . Makatinus africanus n. sp. differs from M. punctatus in the longer body (3228–4128 μm vs 2400–3200 μm); longer odontostyle (31–34 µm vs 25–27 µm) and medial position of vulva (V = 47–52 % vs 56–59 %) ( Heyns 1965). In large body length M. africanus n. sp. is also close to M. capensis Heyns, 1965 , and M. crassiformis ( Kreis, 1924) Andrássy, 1986 . The new species can however be distinguished from M. capensis in the longer odontostyle (31–34 μm vs 24–28 μm), less ventral pores (24–33 vs 48–50) and digitate structure on the tail tip (absent in M. capensis ) ( Heyns 1965). The new species can be distinguished from the type females of M. crassiformis in the higher a-value or thinner body (29.6–39.3 vs 21–27); higher b-value (4.2–4.9 vs 3.6–4.3) and long tail with digitate extension (30–43 μm vs 26 μm without digitate extension) ( Andrássy 1986; Peña-Santiago & Varela 2017). The following, remaining species differ from Makatinus africanus n. sp. in having a body shorter than 2700 μm; an odontostyle shorter than 28 μm and the absence of a digitate struc- ture on the tail: M. aquaticus Jiménez-Guirado, 1994 (L=1920–2260 μm, odontostyle 22–26 μm long) (Peña-San- tiago & Varela 2017); M. heynsi Ahmad & Ahmad, 1992 (L=1960–2420 μm in length, 21–25 μm long odontostyle) ( Ahmad & Ahmad 1992); M. minor ( Loos, 1945) Ahmad, 1997 (L=1900–2200 μm, 21–28 μm long odontostyle)( Ahmad 1997, Peña-Santiago & Varela 2017); M. silvaticus Ahmad, Sturhan & Wouts, 2003 (L=2350–2720 μm, 25–28 μm long odontostyle) ( Ahmad et al. 2003). Makatinus africanus n. sp. could not be compared to M. goodeyi Jiménez-Guirado, 1994 as the latter species is described from males only. However, based on the male body length (2200 μm in M. goodeyi ) and the length of its odontostyle (22 μm in M. goodeyi ) it is unlikely that the females found in the Telperion Nature Reserve belongs to the males of M. goodeyi ( Peña-Santiago & Varela 2017) .

Type material: Holotype female on slide 50559 and paratypes (5 females) on slides 50558–50559 deposited in the National Collection of Nematodes (ARC—Plant Health and Protection, Biosystematics Division, Pretoria).

Type locality: Specimens were found in sediment and water samples collected at the Waterhole 2 site ( Table 1 ). It is located next to road 11_ 26 in the Blaauwpoort 1 section of the reserve and in high rainfall seasons water flows downstream from the Wilge River and collects in this site. Locality number MP00127 in the National Collection of Nematodes (ARC—Plant Health and Protection, Biosystematics Division, Pretoria) .

Etymology: Makatinus africanus n. sp. is named after the continent of origin.

Figures

FIGURE 7. Makatinus africanus n. sp. female A) Anterior region with oesophagus; B) Anterior region with spear and position of amphid; C) Tail region; D) Habitus; E) Vulval region with pars distalis vaginae (pdv), pars refringens vaginae (prv) and pars proximalis vaginae (ppv); F) Reproductive system.

FIGURE 8. Light microscope photos of Makatinus africanus n. sp. female A) Anterior region arrows indicate dorsal median pores; B) Vulval region with pars distalis vaginae (pdv), pars refringens vaginae (prv) and pars proximalis vaginae (ppv); C) Tail region with arrow indicating peg.

Tables

TABLE 3. Morphometrics of Makatinus africanus n. sp. females found in freshwater substrates in the Telperion Nature Reserve. All measurements in the form: mean ± standard deviation (range).

Morphometric feature	Holotype	Paratypes
		n = 5
L	3961	3775 ± 325.4 (3228–4128)
a	39.3	33.9 ± 3.1 (29.6–39.3)
b	4.7	4.6 ± 0.3 (4.2–4.9)
c	112.7	107.3 ± 15.5 (91.8–131.0)
c’	0.6	0.6 ± 0.1 (0.5–0.7)
V %	51	50 ± 1.7 (47–52)
G1 %	17	16 ± 1.4 (14–17)
G2 %	16	16 ± 0.7 (16–17)
Lateral chord as percentage of corresponding body width	17	15 ± 2.5 (12–18)
Aperture as percentage of odontostyle	63.6	63 ± 3.7 (60–70)
Body width at vulva	104	113 ± 11.5 (97–130)
Body width at mid–body	101	112 ± 12.0 (94–126)
Body width at anus	56	59 ± 3.1 (56–63)
Cuticle width at neck	6	6 ± 0.5 (6–7)
Cuticle width at mid–body	7	8 ± 1.3 (7–11)
Cuticle width at dorsal side of tail	11	11 ± 0.8 (9–11)
Lateral chord width	17	17 ± 2.3 (15–20)
Ventral pores (total)	28	28 ± 3.5 (24–33)
Ventral pores (from anterior to end of spear)	3	3a
Ventral pores (from anterior to end of oesophagus)	14	14 ± 1.5 (12–16)
Dorsal pores (total)	6	7 ± 0.8 (6–8)
Dorsal pores (spear)	3	3 ± 0.0 (3)
Dorsal pores (oesophagus)	6	7 ± 0.8 (6–8)
Lateral pores (spear)	4	4 a
Lateral pores (oesophagus)	12	15 ± 1.6 (12–16)
Lip region height	9	8 ± 1.4 (6–10)
Lip region width	28	28 ± 0.7 (27–29)
Amphid aperture width	11	12 ± 1.1 (11–14)
Amphid aperture / corresponding width	38.8	43 ± 5.5 (38–50)
Odontostyle length	31	32 ± 1.1 (31–34)
Odontostyle length (ventral)	27	28 ± 0.5 (27–29)
Odontostyle length (dorsal)	31	32 ± 1.1 (31–34)
Odontophore length	59	60 ± 4.3 (52–65)
Odontostyle aperture length	20	20 ± 1.0 (19–21)
Guide ring from anterior	18	15 ± 2.5 (12–18)
Oesophagus length	851	816 ± 53.4 (747–882)
Basal bulb length	444	444 b
Basal bulb width	61	56 ± 7.2 (51–61)
Cardia length	35	35 ± 1.9 (32–37)

TABLE 3. Morphometrics of Makatinus africanus n. sp. females found in freshwater substrates in the Telperion Nature Reserve. All measurements in the form: mean ± standard deviation (range).

......continued on the next page