Neotrombicula orycti Taufflieb, 1960

Stekolnikov, Alexandr A., Er-Rguibi, Omar, Laghzaoui, El-Mustapha, Aglagane, Abdessamad & Mouden, El Hassan El, 2021, New locality and host records of two chigger mite species (Acariformes: Trombiculidae) from Morocco, Acarologia 61 (3), pp. 538-547 : 541-545

Neotrombicula orycti Taufflieb, 1960 ( Figs 1D , 2 )

Neotrombicula roubaudi var. orycti Taufflieb (1960a) (original designation)

Neotrombicula orycti Stekolnikov (2018b)

Neotrombicula roubaudi var. lemni Taufflieb (1960a) (original designation), n. syn. Neotrombicula lemni Stekolnikov (2018b)

Type material examined — Holotype larva of N. orycti, MNHN 59D 11, ex Oryctolagus [ cuniculus (L.)], Maroc ( MOROCCO), [19]58; paratype larva of N. orycti, MHNG , ex O. cuniculus , Maroc, forêt de Nefifik ( MOROCCO, Nfifikh forest), [19]58; holotype larva of N. lemni, MNHN 59E 16, ex Rattus rattus (L.), Cherrat, Maroc ( MOROCCO, Oued Cherrat), [19]58; paratype larva of N. lemni, MHNG , Maroc, B. Cherrat ( MOROCCO, Oued Cherrat), [19]59.

Additional material examined — Seven larvae ( ZIN 17119 – 17125) from Q. trachyblepharus , MOROCCO, Marrakech province, Oukaïmeden, 28 May 2019, collected by Omar Er-Rguibi, El-Mustapha Laghzaoui, and Abdessamad Aglagane.

Type deposition — The original descriptions of N. orycti and N. lemni did not include an information on the type designation ( Taufflieb 1960a). Currently, the holotype and 10 paratypes of N. orycti are deposited in MNHN (59D 1 – 11) and three paratypes are deposited in MHNG. The holotype and 11 paratypes of N. lemni are deposited in MNHN (59E 1, 5 – 8, 10 – 16) and three paratypes are deposited in MHNG.

Diagnosis — SIF = 7BS-N-3-3111.1000; fPp = B/B/NNB; fD = 2H-(6 – 9)-(6 – 8)-(6

– 7)-(4 – 8)+(5 – 12); DS = 33 – 40; V =27 – 32 ; NDV = 65 – 72 (56 – 80 according to original descriptions of N. orycti and N. lemni ); Ip = 650 – 858 (641 – 888 according to original descriptions); scutum pentagonal, with rounded posterior margin, with moderate number of small puncta; flagelliform sensilla (trichobothria) with ca. 7 branches in distal half; sensillary (trichobothrial) bases anterior to level of PL (by 3 – 6 µm); PL> AL> AM or PL> AM> AL; microtarsala I (ε) distal or proximal to tarsala I (ω); tarsala I longer than tarsala II (26 vs. 18 µm). Standard measurements given in Table 2.

Remarks — Neotrombicula roubaudi ( Vercammen-Grandjean, 1956) was described from Tit Mellil and from Nfifikh forest ( Morocco, Casablanca-Settat region), where it was collected from Apodemus sylvaticus (L.) (syn.: Sylvaemus sylvaticus hayi ), Lemniscomys barbarus (L.), Mus spicilegus Petényi ( Rodentia : Muridae ), and Eliomys munbyanus (Pomel) ( Rodentia : Gliridae ). Later Taufflieb (1960a) described two varieties of N. roubaudi , which were raised to species by Stekolnikov (2018b) with their original author and date, according to ICZN Code, Art. 45.6.4 (ICZN 1999). All three species, N. roubaudi , N. orycti , and N. lemni were found in Nfifikh forest and in Oued Cherrat (a wadi located ca. 23 km NE of Nfifikh forest), on

the level of sensillary bases to extreme anterior margin of scutum; PSB — distance from the level of sensillary bases to extreme posterior margin of scutum; SD — length of scutum (ASB + PSB); P-PL

— distance from the level of posterolateral scutal setae to extreme posterior margin of scutum; AP — distance between antero- and posterolateral scutal seta on one side; AM — length of anteromedian scutal seta; AL — length of anterolateral scutal setae; PL — length of posterolateral scutal setae; S — length of sensilla; H — length of humeral setae; min D — length of the shortest dorsal idiosomal seta; D max — length of the longest dorsal idiosomal seta; min V — length of the shortest ventral idiosomal seta; V max — length of the longest ventral idiosomal seta; pa — length of leg I; pm — length of leg II; pp — length of leg III; Ip — sum of leg lengths (pa + pm + pp); TaIIIL — length of leg tarsus III TaIIIW — width of leg tarsus III; DS — number of dorsal idiosomal setae; V — number of ventral idiosomal setae; NDV — DS + V.

;

L. barbarus , Rattus rattus , Dipodillus campestris (Loche) ( Rodentia : Muridae ), Oryctolagus cuniculus ( Lagomorpha : Leporidae ), and on an inexactly identified passerine bird (“Rouge-

gorge”). Both N. lemni and N. roubaudi were also recorded on E. munbianus , A. sylvaticus , Mus spretus Lataste ( Rodentia : Muridae ), and on Mustela nivalis numidica Pucheran ( Carnivora :

Mustelidae ); the latter species was also recorded on another bird host (“Mésange”, i.e. Paridae gen. sp.).

Taufflieb (1960a) examined and measured rather large samples of these species. He took measurements of scutum for 32 N. lemni and 24 N. orycti specimens; legs were measured for

161 specimens of N. lemni , 58 N. orycti, and 115 N. roubaudi; the number of idiosomal setae was counted for 148 N. lemni and 76 N. orycti. Although ranges of quantitative characters were overlapped for the three species, the following two differences seem significant. The number of idiosomal setae is lower in N. roubaudi than in two other species (NDV = 50 – 58 vs. 56 – 74

in N. lemni and 64 – 80 in N. orycti ). The legs are shorter in N. lemni than in two other species

(Ip = 641 – 800 vs. 775 – 888 in N. orycti and 798 – 922 in N. roubaudi ). Taufflieb also noted that the usual arrangement of setae in first two posthumeral rows is 6- 6 in N. roubaudi , 6-8 in

N. lemni , and 8- 8 in N. orycti . In addition, the microtarsala (famulus, ε) of the leg I is situated at level or slightly distal to tarsala ω () in N. roubaudi , distal to tarsala in N. lemni , and proximal to tarsala in N. orycti ( Taufflieb 1960a) .

We should note that using NDV and Ip allows almost exact discriminating N of. roubaudi from N. orycti + N. lemni : the combination of the latter two species is characterized by NDV>

58 or, if NDV = 56 – 58, then Ip ≤ 800. On the contrary, distinguishing between N. orycti and

1.

Neotrombicula orycti Neotrombicula lemni N. orycti , new material (n = 6)

Holotype Paratype Holotype Paratype Range Mean

AW 71 70 72 70 61-69 66

PW 92 79 86 81 77-84 80

SB 32 28 29 29 25-28 27

ASB 28 31 28 26 25-27 26

PSB 29 31 29 31 27-29 28

SD 57 61 57 57 53-55 54

P-PL 23 - 26 - 23-25 24

AP 29 27 26 25 24-27 26

AM 28 34 34 38 34-40 37

AL 35 41 40 40 31-33 32

PL 48 50 52 56 41-45 43

S - 59 55 70 - -

H 48 51 52 54 45-49 46

Dmin 37 38 40 43 32-36 34

Dmax 38 46 45 55 40-42 41

Vmin 26 23 26 29 23-28 25

Vmax 40 43 42 43 37-40 38

pa 265 311 245 210 281-286 283

pm 231 252 200 197 230-248 240

pp 258 295 242 243 270-292 281

Ip 754 858 686 650 781-824 804

TaIIIL 77 72 79 67 68-76 72

TaIIIW 22 18 18 16 14-15 14

DS 38 40 33 36 - 35

V 27 32 32 29 - 30

NDV 65 72 65 65 - 65

N. lemni by those characters seems unreliable. For example, the holotypes of N. orycti and N. lemni has the same arrangement of setae in first three rows, 6-8-6 ( Fig. 2 ), and identical NDV (65); the only significant quantitative difference between them is Ip = 754 vs. 686 ( Table 2). Meanwhile, as was demonstrated for Hirsutiella zachvatkini (Schluger, 1948) , a difference in the length of legs can characterize intraspecific ecological groups of chiggers, associated with different host species ( Moniuszko et al. 2015).

The position of microtarsala I in relation to the tarsala I is usually treated as a stable taxonomic character ( Stekolnikov & González-Acuña 2012 ; Stekolnikov 2013). We suppose that in N. orycti it is variable. In the examined additional material, microtarsala I is situated distal to tarsala I, like in N. lemni , while all other characters (including Ip and the presence of eight setae in 1 st posthumeral row) fit the diagnosis of N. orycti . Therefore, we conclude that N. lemni cannot be unambiguously discriminated from N. orycti , and synonymize the former species with the latter.

In the additional material, AM> AL, while in all four examined type specimens of N. orycti and N. lemni AL > AM. Since measurements of setae were not given in the original descriptions of these species, significance of this difference is unclear.

Here, N. orycti is for the first time recorded in Marrakech province and on a reptile host.

Figures

Figure 1 Ericotrombidium tarentolae(Vercammen-Grandjean et Langston, 1976), larva ZIN 17115 (A – C): A – scutum; B – genu and tibia II, dorsal aspect; C – tarsus II, dorsal aspect.Neotrombicula oryctiTaufflieb, 1960, larva ZIN 17121: D – scutum. Abbreviations: AL – anterolateral scutal seta; AM – anteromedian scutal seta; PL – posterolateral scutal seta; S – sensillum. Scale bars: A, D – 50 μm; B, C – 20 μm.

Figure 2 Neotrombicula oryctiTaufflieb, 1960, holotype larva: A – dorsal idiosomal setae; B – ventral aspect of idiosoma.Neotrombicula lemni Taufflieb, 1960, holotype larva: C – dorsal idiosomal setae; D – ventral aspect of idiosoma. Abbreviations: cxI – leg coxa I; cxII – leg coxa II; cxIII – leg coxa III; H – humeral seta; sta – anterior sternal setae; stp – posterior sternal setae; V – ventral idiosomal setae; u – uropore (anus).