Gonothrombium oudemansianum ( Feider, 1948 ),

Karakurt, İbrahim, Sevsay, Sevgi & Buğa, Evren, 2016, A review of Gonothrombium Feider, 1950 (Actinotrichida: Microtrombidiidae) with description of a new species from Turkey, Zootaxa 4154 (1), pp. 51-65: 58-64

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Gonothrombium oudemansianum ( Feider, 1948 )


Gonothrombium oudemansianum ( Feider, 1948) 

Diagnosis. Adults. Body colour red in life with four transverse white stripes on each lateral side of dorsal idiosoma and a white stripe at end of dorsal idiosoma. Accessory posterior process of crista metopica short and cylindrical. Stem of pDS spheroidal or stout leaf-like, relatively short, narrowed basally and distally, whole stem covered with fine setules.

Diagnosis. Larvae. Scutellum with multiple (8–15) setae. 3a setae barbed. LSS = 92–110. Tarsal claws formula: 2-2-3.

Description. Adults. Standard measurements in Table 1. Body length 1050–1350, width 741–950 ( Fig. 19View FIGURES 19 – 27). Body colour red when alive with four transversely white stripes on each lateral side of dorsal idiosoma and a white stripe at end of dorsal idiosoma ( Fig. 37View FIGURE 37).

Gnathosoma. Chelicerae and palps typical ( Figs 20, 21View FIGURES 19 – 27). Medial face of palp tibia with two ctenidia and radula. Distal ctenidium with 2-4/2-5 (Lf/Rt) (plus paradont) spinisetae situated behind paradont; proximal ctenidium composed of 3-5/3-6 uniform spinisetae; radula consists of 4-9/4-9 long and very strong spine-like setae ( Fig. 22View FIGURES 19 – 27). Lateral face of palp tibia ( Fig. 23View FIGURES 19 – 27) with one basidont placed at base of palp tarsus and with several long, smooth, whip-like setae at base of odontus. Palp tarsus long and cylindrical with numerous setulose setae and one solenidion laterally, 3–4 solenidia in distal part.

Idiosoma. Aspidosoma triangular in outline. Anterior part of crista metopica short extends to triangular-shaped vertex and bears numerous long, setulose, nonsensillary setae (AM); rounded sensillary area bears two short, smooth sensillary setae; posterior process relatively broad and short; accessory posterior process short and cylindrical. Double and sessile eyes, located at mid-lateral sides of crista metopica; anterior lens larger than posterior lens ( Fig. 24View FIGURES 19 – 27). Dorsal opisthosomal setae ( Fig. 25View FIGURES 19 – 27) of one type, relatively short (10–24) and with thin peduncle. Stem of pDS spheroidal or stout leaf-like, relatively short and whole stem with fine setules. Stems of mid-dorsal setae similar to posterodorsal setae. Ventral setae thin and long (22–30). All setae based on short, cylindrical papillae. External genitalia with three pairs of genital acetabula and composed of a pair of epivalves and centrovalves. Epivalves with dual line of setae and centrovalves with a single line of setae. Epivalves with setulose setae and centrovalves with smooth setae ( Fig. 26View FIGURES 19 – 27).

Legs. Without lamellar processes, shorter than idiosoma. Tarsus I elongate, tibia I shorter than tarsus I ( Fig. 27View FIGURES 19 – 27).

Description. Larvae. Standard measurements in Table 3. All larvae reared from eggs deposited by females in the laboratory. Body length 275–327, 176–229 width. Colour in life red.

G. ozkani  (n=20) G. oudemansianum  (n=20) Character mean Min.–max. Min.–max. L 301 272–319 275–327 W 190 171–214 176–229 L/W 1.58 1.49–1.65 1.48–1.7 AA 45 39–53 30–40

AW 58 51–66 39–47

PW 72 64–76 55–68

SB 35 33–39 29–36

ASB 47 41–51 46–52

PSB 32 29–36 22–30

AP 24 21–28 20–28

AM 48 43–52 32–37

AL 35 31–37 33–36

PL 48 45–54 35–40

S 70 67–77 50–69

MA 17 15–21 15–19

HS 50 48–55 42–50

LSS 126 119–130 92–110 DS MİN. 50 46–54 35–40

DS MAX. 65 63–67 48–58

or 2 2–3 2–3

bs 3 3–4 3–4

1a 45 42–49 38–45

1b 35 33–40 30–38

2b 45 41–50 37–45

3a 20 18–27 27–35

3b 50 47–55 37–46

h1 45 42–48 35–42

h2 40 38–46 28–36

Cx_ I 65 61–69 57–71

Tr_ I 33 27 –38 22–27

bFe_ I 20 16–25 17–23

tFe_ I 30 26 –37 29–36

Ge_ I 20 18–25 19–22

Ti_ I 35 30 –41 30–38

Ta_ I 70 64–77 51–60

Leg I 273 248–294 235–268 Cx_ II 66 53–72 50–62

Tr_ II 28 25 –36 28–35

bFe_ II 20 17–25 15–19

tFe_ II 30 26 –34 22–26

Ge_ II 18 15–23 18–21

Ti_ II 32 28 –38 29–35

Ta_ II 55 50–59 47–55

Leg II 249 226–276 208–243

......continued on the next page G. ozkani  (n=20) G. oudemansianum  (n=20)

Character mean Min.–max. Min.–max. Cx_ III 60 51–68 48–58 Tr_ III 36 29 –40 30–36 bFe_ III 18 16–20 14–17 tFe_ III 33 30 –35 24–27 Ge_ III 18 17–20 15–22 Ti_ III 34 30 –36 29–35 Ta_ III 62 55–68 46–54 Leg III 261 239–273 215–241 IP 783 734–825 671–739

Gnathosoma. Subterminal internal edge of cheliceral blades with a small tooth. Adoral setae short and smooth. Hypostomal setae (bs) spine-like. Palp femur and genu without seta. Palp tibia with three setae: a long, nude seta, a spine-like seta and a minute seta. Palp tibial claws bifid. Palp tarsus with one solenidion, two eupathidia, three long nude setae and a short nude seta ( Fig. 28View FIGURES 28 – 30). f Pp formula: 0-0-0-NNN2-NNNNωζζ.

Idiosoma dorsum ( Fig. 29View FIGURES 28 – 30). Scutum pentagonal; middle of lateral borders slightly concave, anterior border and middle of posterior border convex. Transverse line anterior to AM bases of scutum and remaining part longitudinally striate and punctate, with three pairs of nonsensillary and one pair of sensillary setae. AM, AL and PL setae barbed. AM and PL setae subequal in length, AL seta shorter than AM and PL. S setae with few barbs in middle of stem. Pair of double-lensed eyes situated in posterior half of scutum. Anterior lens larger than posterior lens. Scutellum wider than scutum, with longitudinal striations, punctate, and bearing multiple (8–15) barbed setae. All dorsal setae situated on plates (each plate almost same width), barbed and arranged in five rows. C row with 6 + (8–15) setae, D and E rows with 8–10 setae, F row with 6–7 setae. H row typically bears 4 setae. Length of dorsal setae 35–58 (shortest setae in H row).

Idiosoma venter ( Fig. 30View FIGURES 28 – 30). Claparéde’s organs laterally between coxae I and coxae II. ƒCx formula: BB-B-B. One pair of intercoxal setae 3a barbed. Four pairs of opisthoventral barbed setae situated on platelets. ƒV formula: 2-2u-4. Ventral setae slightly thinner than dorsal setae.

Legs ( Figs. 31–36View FIGURES 31 – 36). Leg segmentation formula:6-6-6 (femora of legs ventrally divided, with slight line of fusion evident). All of them punctate. Legs setal formula: [I] Tr (1B) – Fe (5B, 1N) – Ge (4B, 2σ, 1κ) – Ti (6B, 2φ, 1κ) – Ta (17B, 2ζ, 1ω, 1ε); [II] Tr (1B) – Fe (4B, 1N) – Ge (2B, 1σ) – Ti (5B, 2φ) – Ta (14B, 1ζ 1ω, 1ε); [III] Tr (1B) – Fe (3B, 1N) – Ge (2B, 1σ) – Ti (5B) – Ta (13B). Solenidion on tarsus I backwardly curved. Tarsus I and tarsus II with two trifurcate claws; tarsus III with a pair of trifurcate claws and a slender claw-like empodium.

Material examined. Two females collected in Kop gateway, Bayburt Province, Turkey (40°06'58'' N, 40°25'19'' E, 1906 m a.s.l., litter with copse and 40°02'10'' N, 40°30'46'' E, 2429 m a.s.l., moist moss, 30.05.2013, leg. İ. Karakurt and H. H. Özbek)GoogleMaps  . Two females collected in Ahmediye pond, Erzincan Province, Turkey (39°52'54" N, 39°20'19" E, 2012 m a.s.l., moist moss, 26.05.2014, leg. E. Buğa)GoogleMaps  . One female collected in Ekşisu marsh, Erzincan Province, Turkey (39°42'46" N, 39°37'08" E, 1158 m a.s.l., moist moss, 27.04.2015, leg. G. Adıgüzelli)GoogleMaps  . Larvae obtained from females by experimental rearing. The materials were deposited in Biology Laboratory of Erzincan University, Erzincan, Turkey. 

Distribution. Romania and Turkey.

Laboratory observations. Laboratory data is given Table 4.

Adults of Gonothrombium  seem similar to adults of Atractothrombium  because they have a basidont and similar crista region. These genera are separated from each other by the shape of the pDS, which have a peduncle in Gonothrombium  but not in Atractothrombium  . Larval characters also separate the genera, as the scutellum bears multiple setae (8–18) in Gonothrombium  whereas it bears two setae in Atractothrombium  .

Adults of Gonothrombium ozkani  sp. nov. have several character states not found in other species of Gonothrombium  as follows: the idiosomal dorsum lacks white stripes ( G. oudemansianum  ( Fig. 37View FIGURE 37) and G. bimaculatum  have white stripes); the stem of pDS is relatively thin, long and narrows towards the tip in G. ozkani  sp. nov. (rod-like, slightly widened towards tip in G. bimaculatum  ; spheroidal or stout leaf-like and short (10–24) in G. oudemansianum  ); and the shape of the accessory process is hammer-like in G. o z k a n i sp. nov. (cylindrical in the other two species).

Larvae of G. ozkani  sp. nov. differ from G. bequaerti  in some character states, as follows: the whole scutum of G. ozkani  sp. nov. is longitudinally striate (transverse line up to AM bases and whole remaining part longitudinally striate in G. bequaerti (Oudemans 1912))  ; the scutellum of G. ozkani  sp. nov. bears 10–14 barbed setae ( G. bequaerti  has 18 ( Oudemans 1911, 1912)); the number of dorsal setae (including setae on scutellum) is 42–50 in G. ozkani  sp. nov. [According to Oudemans (1912) 96 in G. bequaerti  (op. cit., p. 119)].

Feider (1955) compared the larvae of G. oudemansianum  and G. bimaculatum  but some of his data presented, especially information relating to the leg setal formulae in his “ Table 5 ” (op. cit., p. 463 for G. oudemansianum  ) were not verified. In additional to this, Feider (1955) illustrated the tarsal claws formula as 3-3- 3 in both larval species; however, the formulae of tarsal claws was found to be 2-2-3 by Oudemans (1912) and Thor & Willmann (1947) as well as our work.

Larvae of G. o z k a n i sp. nov. differ from G. oudemansianum  by the shape of 3a setae. While these setae are nude in G. ozkani  sp. nov., they are barbed in G. oudemansianum ( Feider 1955)  . Larvae of G. ozkani  sp. nov. are similar to G. bimaculatum  but the length of LSS are different, being 119–130 in G. ozkani  sp. nov. but just 54 in G. bimaculatum ( Feider 1955)  . Comparisons of characters for these species are given in Table 5.

Numbers of setae on 10–14 8–15 13 ( Feider 1955) scutellum

TABLE 4. Laboratory data on G. oudemansianum females.

  Oviposition date Eggs Prelarval stage Number of larvae

TABLE 5. Comparing some characters of G. oz kani sp. nov., G. oudemansianum and G. bimaculatum.

  G. ozkani  sp. nov.  
AD White stripes on idiosoma (dorsum)    
    35–40/48–58 mean 50 (Feider 1955)